fix(ci): add IMPORT_HOST_DIR stub to compose-idempotency env file

Docker Compose interpolates all variables in the full file even when
only a subset of services is requested. The backend service uses
IMPORT_HOST_DIR with :? (hard-required), causing the idempotency job
to abort before any container starts. A dummy path satisfies the parser;
the backend service is never started in this job so the path need not exist.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -36,18 +36,55 @@ jobs:
         run: npm run lint
         working-directory: frontend
 
+      - name: Assert no banned vi.mock patterns
+        shell: bash
+        run: |
+          # Literal pdfjs-dist (libLoader pattern — ADR 012)
+          if grep -rF "vi.mock('pdfjs-dist'" frontend/src/; then
+            echo "FAIL: banned vi.mock('pdfjs-dist') pattern found — see ADR 012. Use the libLoader prop injection pattern instead."
+            exit 1
+          fi
+          # Async factory with dynamic import in body (named mechanism — ADR 012 / #553).
+          # Multiline PCRE matches `vi.mock(<arg>, async ... { ... await import(...) ... })`
+          # across line breaks. __meta__ is excluded because it contains fixture strings
+          # demonstrating the very pattern this check is meant to forbid.
+          if grep -rPzln 'vi\.mock\([^)]+,\s*async[^{]*\{[\s\S]*?await\s+import\s*\(' \
+              --include='*.spec.ts' --include='*.test.ts' \
+              --exclude-dir='__meta__' \
+              frontend/src/; then
+            echo "FAIL: banned async vi.mock factory with dynamic import in body — see ADR 012 / #553. Use a synchronous factory + vi.hoisted instead."
+            exit 1
+          fi
+
       - name: Run unit and component tests with coverage
-        run: npm run test:coverage
+        shell: bash
+        run: |
+          set -eo pipefail
+          npm run test:coverage 2>&1 | tee /tmp/coverage-test-${{ github.run_id }}.log
         working-directory: frontend
         env:
           TZ: Europe/Berlin
 
+      # Diagnostic guard: covers the coverage run only. If `npm test` (above)
+      # exits 1 with a birpc error, the named pattern appears here — not there.
+      - name: Assert no birpc teardown race in coverage run
+        shell: bash
+        if: always()
+        run: |
+          if grep -qF "[birpc] rpc is closed" /tmp/coverage-test-${{ github.run_id }}.log 2>/dev/null; then
+            echo "FAIL: [birpc] rpc is closed teardown race detected in coverage run"
+            grep -F "[birpc] rpc is closed" /tmp/coverage-test-${{ github.run_id }}.log
+            exit 1
+          fi
+
       - name: Upload coverage reports
         if: always()
         uses: actions/upload-artifact@v4
         with:
           name: coverage-reports
-          path: frontend/coverage/
+          path: |
+            frontend/coverage/
+            /tmp/coverage-test-${{ github.run_id }}.log
 
       - name: Build frontend
         run: npm run build
@@ -232,6 +269,7 @@ jobs:
           MAIL_HOST=mailpit
           MAIL_PORT=1025
           APP_MAIL_FROM=noreply@local
+          IMPORT_HOST_DIR=/tmp/dummy-import
           EOF
 
       - name: Bring up minio

.gitea/workflows/coverage-flake-probe.yml

@@ -0,0 +1,64 @@
+name: Coverage Flake Probe
+
+# Manually-triggered probe for the birpc teardown race documented in ADR 012
+# / #553. Runs the full coverage suite 20× in parallel against a single SHA
+# and asserts zero `[birpc] rpc is closed` lines across every cell. Verifies
+# the acceptance criterion that the race no longer surfaces under coverage.
+
+on:
+  workflow_dispatch:
+
+jobs:
+  coverage-flake-probe:
+    name: Coverage flake probe (run ${{ matrix.run }})
+    runs-on: ubuntu-latest
+    container:
+      image: mcr.microsoft.com/playwright:v1.58.2-noble
+    strategy:
+      fail-fast: false
+      matrix:
+        run: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Cache node_modules
+        id: node-modules-cache
+        uses: actions/cache@v4
+        with:
+          path: frontend/node_modules
+          key: node-modules-${{ hashFiles('frontend/package-lock.json') }}
+
+      - name: Install dependencies
+        if: steps.node-modules-cache.outputs.cache-hit != 'true'
+        run: npm ci
+        working-directory: frontend
+
+      - name: Compile Paraglide i18n
+        run: npx @inlang/paraglide-js compile --project ./project.inlang --outdir ./src/lib/paraglide
+        working-directory: frontend
+
+      - name: Run unit and component tests with coverage
+        shell: bash
+        run: |
+          set -eo pipefail
+          npm run test:coverage 2>&1 | tee /tmp/coverage-test-${{ github.run_id }}-${{ matrix.run }}.log
+        working-directory: frontend
+        env:
+          TZ: Europe/Berlin
+
+      - name: Assert no birpc teardown race
+        shell: bash
+        if: always()
+        run: |
+          if grep -qF "[birpc] rpc is closed" /tmp/coverage-test-${{ github.run_id }}-${{ matrix.run }}.log 2>/dev/null; then
+            echo "FAIL: [birpc] rpc is closed teardown race detected in run ${{ matrix.run }}"
+            grep -F "[birpc] rpc is closed" /tmp/coverage-test-${{ github.run_id }}-${{ matrix.run }}.log
+            exit 1
+          fi
+
+      - name: Upload coverage log on failure
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-log-run-${{ matrix.run }}
+          path: /tmp/coverage-test-${{ github.run_id }}-${{ matrix.run }}.log

.gitea/workflows/nightly.yml

@@ -158,28 +158,38 @@ jobs:
         # public surface works. This step catches: Caddy not reloaded, HSTS
         # header dropped, /actuator block bypassed.
         #
-        # --resolve pins staging.raddatz.cloud to the runner's loopback so we
-        # do NOT depend on the host router doing hairpin NAT (many SOHO
-        # routers do not, or do so only after a firmware update). SNI still
-        # uses the public hostname so the cert validates correctly.
+        # --resolve pins staging.raddatz.cloud to the Docker bridge gateway IP
+        # (the host) so we do NOT depend on hairpin NAT on the host router.
+        # 127.0.0.1 cannot be used: job containers run in bridge network mode
+        # (runner-config.yaml), so 127.0.0.1 is the container's loopback, not
+        # the host's. The bridge gateway IS the host; Caddy binds 0.0.0.0:443
+        # and is therefore reachable from the container via that IP.
+        # SNI still uses the public hostname so the TLS cert validates correctly.
+        #
+        # Gateway detection reads /proc/net/route (always present, no package
+        # required) instead of `ip route` to avoid a dependency on iproute2.
+        # Field $2=="00000000" is the default route; field $3 is the gateway as
+        # a little-endian 32-bit hex value which awk decodes to dotted-decimal.
         run: |
           set -e
           HOST="staging.raddatz.cloud"
           URL="https://$HOST"
-          RESOLVE="--resolve $HOST:443:127.0.0.1"
-          echo "Smoke test: $URL (pinned to 127.0.0.1)"
-          curl -fsS $RESOLVE --max-time 10 "$URL/login" -o /dev/null
+          HOST_IP=$(awk 'NR>1 && $2=="00000000"{h=$3;printf "%d.%d.%d.%d\n",strtonum("0x"substr(h,7,2)),strtonum("0x"substr(h,5,2)),strtonum("0x"substr(h,3,2)),strtonum("0x"substr(h,1,2));exit}' /proc/net/route)
+          [ -n "$HOST_IP" ] || { echo "ERROR: could not detect Docker bridge gateway via /proc/net/route"; exit 1; }
+          RESOLVE="--resolve $HOST:443:$HOST_IP"
+          echo "Smoke test: $URL (pinned to $HOST_IP via bridge gateway)"
+          curl -fsS "$RESOLVE" --max-time 10 "$URL/login" -o /dev/null
           # Pin the preload-list-eligible HSTS value, not just header presence:
           # a degraded `max-age=1` or a dropped `includeSubDomains; preload` must
           # fail this check rather than pass it silently.
-          curl -fsS $RESOLVE --max-time 10 -I "$URL/" \
+          curl -fsS "$RESOLVE" --max-time 10 -I "$URL/" \
             | grep -Eqi 'strict-transport-security:[[:space:]]*max-age=31536000.*includeSubDomains.*preload'
           # Permissions-Policy denies APIs the app does not use (camera,
           # microphone, geolocation). A regression that loosens or drops the
           # header now fails the smoke step.
-          curl -fsS $RESOLVE --max-time 10 -I "$URL/" \
+          curl -fsS "$RESOLVE" --max-time 10 -I "$URL/" \
             | grep -Eqi 'permissions-policy:[[:space:]]*camera=\(\),[[:space:]]*microphone=\(\),[[:space:]]*geolocation=\(\)'
-          status=$(curl -s $RESOLVE -o /dev/null -w "%{http_code}" --max-time 10 "$URL/actuator/health")
+          status=$(curl -s "$RESOLVE" -o /dev/null -w "%{http_code}" --max-time 10 "$URL/actuator/health")
           [ "$status" = "404" ] || { echo "expected 404 from /actuator/health, got $status"; exit 1; }
           echo "All smoke checks passed"
 

.gitea/workflows/release.yml

@@ -107,26 +107,28 @@ jobs:
 
       - name: Smoke test deployed environment
         # See nightly.yml — same three checks, against the prod vhost.
-        # --resolve pins archiv.raddatz.cloud to the runner's loopback so
-        # the smoke test does NOT depend on hairpin NAT on the host router.
+        # --resolve pins to the bridge gateway IP (the host), not 127.0.0.1
+        # — see nightly.yml for the full network topology explanation.
         run: |
           set -e
           HOST="archiv.raddatz.cloud"
           URL="https://$HOST"
-          RESOLVE="--resolve $HOST:443:127.0.0.1"
-          echo "Smoke test: $URL (pinned to 127.0.0.1)"
-          curl -fsS $RESOLVE --max-time 10 "$URL/login" -o /dev/null
+          HOST_IP=$(ip route show default | awk '/default/ {print $3}')
+          [ -n "$HOST_IP" ] || { echo "ERROR: could not detect Docker bridge gateway via 'ip route'"; exit 1; }
+          RESOLVE="--resolve $HOST:443:$HOST_IP"
+          echo "Smoke test: $URL (pinned to $HOST_IP via bridge gateway)"
+          curl -fsS "$RESOLVE" --max-time 10 "$URL/login" -o /dev/null
           # Pin the preload-list-eligible HSTS value, not just header presence:
           # a degraded `max-age=1` or a dropped `includeSubDomains; preload` must
           # fail this check rather than pass it silently.
-          curl -fsS $RESOLVE --max-time 10 -I "$URL/" \
+          curl -fsS "$RESOLVE" --max-time 10 -I "$URL/" \
             | grep -Eqi 'strict-transport-security:[[:space:]]*max-age=31536000.*includeSubDomains.*preload'
           # Permissions-Policy denies APIs the app does not use (camera,
           # microphone, geolocation). A regression that loosens or drops the
           # header now fails the smoke step.
-          curl -fsS $RESOLVE --max-time 10 -I "$URL/" \
+          curl -fsS "$RESOLVE" --max-time 10 -I "$URL/" \
             | grep -Eqi 'permissions-policy:[[:space:]]*camera=\(\),[[:space:]]*microphone=\(\),[[:space:]]*geolocation=\(\)'
-          status=$(curl -s $RESOLVE -o /dev/null -w "%{http_code}" --max-time 10 "$URL/actuator/health")
+          status=$(curl -s "$RESOLVE" -o /dev/null -w "%{http_code}" --max-time 10 "$URL/actuator/health")
           [ "$status" = "404" ] || { echo "expected 404 from /actuator/health, got $status"; exit 1; }
           echo "All smoke checks passed"
 

docs/adr/012-browser-test-mocking-strategy.md

@@ -0,0 +1,134 @@
+# ADR 012 — Browser-Mode Test Mocking Strategy
+
+**Status:** Accepted  
+**Date:** 2026-05-11 (revised 2026-05-12)  
+**Issues:** [#535 — original incident](https://git.raddatz.cloud/marcel/familienarchiv/issues/535) · [#553 — revision](https://git.raddatz.cloud/marcel/familienarchiv/issues/553)
+
+---
+
+## Context
+
+Vitest browser-mode tests (the `client` project, run with `@vitest/browser-playwright` / Chromium) use a different module resolution path than Node-environment tests. When a spec calls `vi.mock('some-module', factory)`, vitest registers a `ManualMockedModule`. At runtime, every time Chromium requests that module, a playwright route handler intercepts the request and calls the Node worker over **birpc** (`resolveManualMock`) to evaluate the factory and return the module body.
+
+This is safe for modules that are imported **statically** at spec module-eval time (e.g. `$app/navigation`, `$env/static/public`): those requests resolve before the first test runs and well before any teardown occurs.
+
+It is **unsafe** for modules that are imported **dynamically** (e.g. inside an `async onMount`, inside a lazy-loaded chunk): Chromium may fetch the module after the worker's birpc channel has already closed, producing:
+
+```
+Error: [birpc] rpc is closed, cannot call "resolveManualMock"
+  ❯ ManualMockedModule.factory   node_modules/@vitest/browser/dist/index.js:3221:34
+```
+
+This raises an unhandled rejection that exits the vitest process with code 1, even though every test in the run reported green.
+
+`pdfjs-dist` and `pdfjs-dist/build/pdf.worker.min.mjs?url` are loaded via `await Promise.all([import('pdfjs-dist'), import('pdfjs-dist/build/pdf.worker.min.mjs?url')])` inside `usePdfRenderer.svelte.ts::init()`, which is called from `onMount`. These dynamic imports triggered the race.
+
+---
+
+## Decision
+
+**Prefer prop injection over `vi.mock(module, factory)` for any module that is loaded dynamically in browser-mode specs.**
+
+### The libLoader pattern (for external rendering libraries)
+
+When a component depends on a large external library loaded via dynamic import, extract the import into an injectable loader function with a production default:
+
+```typescript
+// usePdfRenderer.svelte.ts
+type LibLoader = () => Promise<readonly [typeof import('pdfjs-dist'), { default: string }]>;
+
+const defaultLibLoader: LibLoader = () =>
+  Promise.all([import('pdfjs-dist'), import('pdfjs-dist/build/pdf.worker.min.mjs?url')]);
+
+export function createPdfRenderer(libLoader: LibLoader = defaultLibLoader) { ... }
+```
+
+The component threads the loader as an optional prop:
+
+```svelte
+<!-- PdfViewer.svelte -->
+let { url, ..., libLoader = undefined } = $props();
+const renderer = untrack(() => createPdfRenderer(libLoader));
+```
+
+Tests supply a synchronous fake — no `vi.mock` needed:
+
+```typescript
+const fakePdfjs = { GlobalWorkerOptions: ..., getDocument: vi.fn(), TextLayer: class {} };
+const fakeLoader = vi.fn().mockResolvedValue([fakePdfjs, { default: '' }] as const);
+render(PdfViewer, { url: '...', libLoader: fakeLoader });
+```
+
+### The test-host pattern (for component behaviour)
+
+For components that fetch data or call services, the `*.test-host.svelte` pattern threads the dependency as a prop rather than mocking the module. See `PersonMentionEditor.test-host.svelte` for the canonical example.
+
+---
+
+## Binding invariant: factory bodies must be synchronous (#553)
+
+The original revision of this ADR allowed `vi.mock(virtualModule, factory)` for SvelteKit/Vite virtual modules on the argument that their consumer imports were resolved at static-import time. **That reasoning is wrong.** What matters is what the **factory body** does, not where the mocked module is consumed.
+
+`EnrichmentBlock.svelte.spec.ts` (issue #553) was statically imported and still produced the race: its `vi.mock('$app/stores', async () => { const mod = await import(...); return mod; })` factory performed a dynamic import in its body, and that body was invoked asynchronously when Chromium fetched the manually-mocked module — sometimes after the worker's birpc channel had already closed.
+
+**Therefore: under `**/*.svelte.{test,spec}.ts`, every `vi.mock` factory body must be synchronous. No `await`, no `import(...)`.**
+
+If a factory needs to share state with the spec (a mutable ref, a `vi.fn`, a writable store), use `vi.hoisted()` to lift the reference above `vi.mock`'s implicit hoist:
+
+```ts
+const { mockNavigating } = vi.hoisted(() => ({
+    mockNavigating: { type: null as string | null }
+}));
+
+vi.mock('$app/state', () => ({
+    get navigating() {
+        return mockNavigating;
+    }
+}));
+```
+
+The getter defers the read until consumption time; `vi.hoisted` guarantees the reference is initialised before the (also hoisted) `vi.mock` factory runs. See `DropZone.svelte.spec.ts:9`, `NotificationBell.svelte.spec.ts:6-10`, and `EnrichmentBlock.svelte.spec.ts` for canonical examples.
+
+### Architectural follow-on: prefer `$app/state` over `$app/stores`
+
+`$app/stores` is the deprecated subscription-based store API; `$app/state` is the modern reactive proxy. New components should import from `$app/state`. As part of #553 we migrated `EnrichmentBlock.svelte` from `$app/stores.navigating` to `$app/state.navigating` with `!!navigating.type` — matching the pattern already established in `routes/aktivitaeten/+page.svelte:117` and `routes/documents/+page.svelte:261`. Migration eliminated the *need* to mock a store at all in that spec.
+
+**Pattern note:** When an overlay or dropdown triggers a navigation action, use `<button type="button">` with an `onclick` handler that calls `goto(path)` — do **not** use `<a href="…">` with `e.preventDefault()`. SvelteKit registers its link interceptor as a capture-phase `document` listener, so it fires before the component's bubble-phase `onclick`. By the time `e.preventDefault()` runs the router has already initiated navigation, which tears down the vitest-browser Playwright orchestrator iframe. A `<button>` carries no `href`, so the capture-phase interceptor never fires. See `NotificationDropdown.svelte` for the canonical example.
+
+**Pattern note (#553):** Browser-mode tests run with `data-sveltekit-preload-data="off"` (set in `src/test-setup.ts` via the client project's `setupFiles`). Hover-prefetch otherwise fires real fetch requests for route loader chunks; those requests go through the same Playwright route handler that serves mocked modules. An in-flight prefetch landing after iframe teardown can hit the handler with a closed birpc channel, raising an unhandled rejection.
+
+---
+
+## Binding invariant: one canonical ID per mocked module (#553 — duplicate-id hazard)
+
+The sync-factory invariant above closes one named trigger of the `[birpc] rpc is closed` race. Investigation of a follow-up flake revealed a second, independent trigger: **the same resolved module URL mocked under two distinct ID strings** across or within spec files.
+
+`@vitest/browser-playwright` registers a Playwright `page.context().route(...)` handler per `vi.mock` call. The predicate matches on the module's resolved URL. When two `vi.mock` calls reference the same module under different IDs — for example `'$lib/foo.svelte'` and `'$lib/foo.svelte.js'` (both resolve to the same Svelte rune-module URL) — the registry stores both predicates but the cleanup map only tracks the latest. The orphan route survives session teardown. When the next session loads the same module, the orphan fires, calls `await module.resolve()` against a closed birpc channel, and crashes the run.
+
+This is fixed upstream in [vitest PR #10267](https://github.com/vitest-dev/vitest/pull/10267) (issue [#9957](https://github.com/vitest-dev/vitest/issues/9957)). Until that fix reaches a published `@vitest/browser-playwright` release, we close the gap from two sides:
+
+**The rule.** Every mocked module must be referenced under exactly one ID string across the entire client test suite. Pick the spelling production code uses. For Svelte 5 rune modules (`*.svelte.ts`), the canonical form is the no-extension import (`'$lib/foo.svelte'`) — matches the source file basename and matches Svelte 5 convention. Never mix `.svelte.js` and `.svelte` for the same module across specs.
+
+**Enforcement layers** (added in #553's second cycle, extending the four-layer chain above):
+
+5. **In-suite meta-test** at `frontend/src/__meta__/no-duplicate-mock-ids.test.ts` globs `src/**/*.svelte.{test,spec}.ts`, extracts every `vi.mock` first-arg string, canonicalises by stripping a trailing `.js`/`.ts` after `.svelte`, and fails if any canonical ID is referenced under two or more distinct spellings. Same shape as `no-async-mock-factories.test.ts`.
+6. **`patch-package` backport** of PR #10267 at `frontend/patches/@vitest+browser-playwright+4.1.0.patch`. Applied automatically by the `postinstall` hook. Closes the race at the route-handler level — even if a contributor reintroduces a duplicate-ID, the patched `register` handler unroutes the existing predicate before installing the new one.
+
+**When to remove the patch.** Once `@vitest/browser-playwright` ships a release containing PR #10267, delete `patches/@vitest+browser-playwright+4.1.0.patch`. Bump the dependency to the version containing the fix. The in-suite meta-test stays — it's a cheap permanent guard against the contributor-facing pattern, independent of upstream library version.
+
+---
+
+## Consequences
+
+- New browser-mode specs that need to stub an external library **must not** use `vi.mock(externalLib, factory)`. Add a loader/factory parameter to the underlying hook or service instead.
+- The CI `unit-tests` job includes a permanent grep guard that fails the build if `rpc is closed` appears in any coverage run log. This catches regressions before they reach the acceptance criterion.
+- Acceptance criterion for #535: 60 consecutive green `workflow_dispatch` CI runs against `main` after the fix is merged, with zero `rpc is closed` lines in any log.
+- **Enforcement (six layers, defence in depth):**
+  1. **ESLint `no-restricted-syntax`** in `eslint.config.js` (scoped to `**/*.{spec,test}.ts`) flags two patterns: (a) the literal `vi.mock('pdfjs-dist', ...)` — enforces the libLoader pattern — and (b) any `vi.mock(..., async () => { ... await import(...) ... })` — enforces the synchronous-factory invariant. Both messages point at this ADR. Failure surfaces at save time.
+  2. **CI grep guard** in `.gitea/workflows/ci.yml` runs before the test suite launches. Mirrors the ESLint patterns with `grep -Pzn`. ~10s round-trip.
+  3. **In-suite meta-test** at `frontend/src/__meta__/no-async-mock-factories.test.ts` globs `src/**/*.svelte.{test,spec}.ts` and asserts none match the banned pattern. Catches at every vitest invocation — the layer hardest to disable.
+  4. **CI birpc assert** runs after the coverage step and fails the build if `[birpc] rpc is closed` appears in any log line. Catches the symptom even if all the upstream layers were bypassed.
+  5. **In-suite duplicate-ID meta-test** at `frontend/src/__meta__/no-duplicate-mock-ids.test.ts` enforces the one-canonical-ID-per-module rule from the duplicate-id-hazard section above.
+  6. **`patch-package` backport** at `frontend/patches/@vitest+browser-playwright+4.1.0.patch` closes the upstream race itself, applied via `postinstall`. To be removed when `@vitest/browser-playwright` releases [vitest PR #10267](https://github.com/vitest-dev/vitest/pull/10267).
+- **Acceptance verification:** `coverage-flake-probe.yml` is a `workflow_dispatch`-triggered matrix workflow that runs the coverage suite 20× in parallel against a single SHA and asserts zero birpc lines. One fire, parallel cost, deterministic signal — replaces accumulating 20 sequential push events.
+- **When to revisit the LibLoader home:** If three or more components adopt this pattern, consider extracting a shared `$lib/types/lib-loader.ts` or a generic `DynamicImportLoader<T>` type to avoid parallel type definitions across modules.

docs/adr/013-client-branches-coverage-threshold.md

@@ -0,0 +1,92 @@
+# ADR 013 — Client-Project Branch Coverage Threshold
+
+**Status:** Accepted  
+**Date:** 2026-05-14  
+**Issues:** [#556 — threshold drop](https://git.raddatz.cloud/marcel/familienarchiv/issues/556) · [#496 — long-tail-grind tracking](https://git.raddatz.cloud/marcel/familienarchiv/issues/496)
+
+---
+
+## Context
+
+The browser-mode component test suite (`vitest.client-coverage.config.ts`) enforces Istanbul coverage thresholds across `lines`, `functions`, `branches`, and `statements`. The `branches` metric was set to 80%, but the codebase sits at **75%** — below the gate — causing every CI run of `unit-tests` and `coverage-flake-probe` to fail on this check alone, even when all tests are green.
+
+**Measured baseline (2026-05-14, branch `feat/issue-553-birpc-async-mock-factory`, head `2e6cc346`):**
+
+```
+branches:   75%  (below the 80% gate — reason for this ADR)
+lines:      ≥ 80%
+functions:  ≥ 80%
+statements: ≥ 80%
+```
+
+Reproducer:
+
+```bash
+cd frontend && npm ci && npx vitest run -c vitest.client-coverage.config.ts --coverage
+```
+
+### The long-tail-grind problem
+
+In Istanbul's branch accounting, when a child component gains test coverage its branches are added to the parent's denominator. A child moving from 40% → 80% coverage can drag a parent from 78% → 72% because more branches in the call graph become reachable and must be covered. This is not a bug — it is how branch accounting works — but it means that on a large SvelteKit application the denominator grows with every coverage improvement, making an arbitrary 80% ceiling a constant grind. Per #496, the expected cost to reach 80% branches from 75% is 30–100+ commits with no guarantee of stability.
+
+### Why this layer is different
+
+The 80% branch floor used for backend unit/integration tests is appropriate for Java service code and permission logic. Browser-mode component coverage measures Svelte template branches: conditional class bindings, `{#if}` blocks, empty/loaded/error state guards. These branches have a fundamentally different accounting model and a higher inherent denominator. This ADR **only** lowers the browser-mode component gate; the backend test coverage gates are unaffected.
+
+### Security-relevant uncovered components
+
+The following auth/permission-boundary components currently have low or zero branch coverage. When ratchet-up work begins (see below), these are the highest-priority targets:
+
+- `src/routes/login/+page.svelte`
+- `src/routes/forgot-password/+page.svelte`
+- `src/routes/reset-password/+page.svelte`
+- `src/routes/register/+page.svelte`
+
+Note: the 75% figure already reflects the absence of coverage on these files. Lowering the gate does not create this gap — it makes the existing state legible.
+
+---
+
+## Decision
+
+Drop the `branches` threshold from `80` → `75` in `frontend/vitest.client-coverage.config.ts`. Leave `lines`, `functions`, and `statements` at `80`.
+
+The 75% figure matches the measured current state, allowing CI to pass while deliberate coverage improvement work (tracked in #496) continues without blocking other PRs. The asymmetry in the thresholds block is intentional and documented with an inline comment pointing here.
+
+---
+
+## Ratchet Rule
+
+The branches threshold ratchets **up by 3 percentage points** when the rolling 3-PR-average client-project branches figure on `main` stays at or above `threshold + 3pp` for ≥ 30 consecutive days. Direction is **up-only** — never lower the floor below 75 without a new ADR superseding this one. Manual today (verify before any `vitest.client-coverage.config.ts` edit); a future automation issue may codify the check.
+
+Concretely:
+- When `main` sustains ≥ 78% branches across 3 consecutive PRs for 30 days → raise gate to 78%
+- When `main` sustains ≥ 81% branches across 3 consecutive PRs for 30 days → raise gate back to 80%
+
+---
+
+## Non-goals
+
+- **Not** raising actual branch coverage — that is #496's job, tracked separately.
+- **Not** touching the server-project coverage configuration (`vitest.config.ts`) — only the client project hits the long-tail-grind pattern.
+- **Not** removing or relaxing any existing test files, `skipIf` guards, or axe-playwright accessibility runs.
+
+---
+
+## Consequences
+
+**Easier:**
+- CI unblocked — `unit-tests` and `coverage-flake-probe` jobs pass when all tests are green
+- The ratchet rule creates a concrete, observable path back to 80%
+
+**Harder:**
+- The gate now has near-zero headroom — any branch regression that drops below 75% will fail CI immediately
+- The 75% floor must not be treated as a permanent ceiling; the ratchet discipline requires active attention
+
+---
+
+## References
+
+- [#496 — Branch coverage long-tail grind](https://git.raddatz.cloud/marcel/familienarchiv/issues/496)
+- [#556 — This threshold drop](https://git.raddatz.cloud/marcel/familienarchiv/issues/556)
+- [ADR 012 — Browser-Mode Test Mocking Strategy](./012-browser-test-mocking-strategy.md)
+- `frontend/vitest.client-coverage.config.ts` — thresholds block (lines 44–51)

frontend/eslint.config.js

@@ -72,6 +72,31 @@ export default defineConfig(
 			]
 		}
 	},
+	{
+		files: ['**/*.spec.ts', '**/*.test.ts'],
+		rules: {
+			'no-restricted-syntax': [
+				'error',
+				{
+					selector:
+						"CallExpression[callee.object.name='vi'][callee.property.name='mock'] > Literal[value=/^pdfjs-dist/]",
+					message:
+						"Banned: vi.mock('pdfjs-dist', factory) causes a birpc teardown race in browser-mode specs — see ADR 012. Use the libLoader prop injection pattern instead."
+				},
+				{
+					// ADR 012 / #553. The named mechanism: an async vi.mock factory whose
+					// body performs `await import(...)` produces a late birpc roundtrip
+					// during worker teardown. The factory body must be synchronous; if
+					// you need to share state between the spec and the mock, use
+					// `vi.hoisted` (see DropZone.svelte.spec.ts).
+					selector:
+						"CallExpression[callee.object.name='vi'][callee.property.name='mock'][arguments.1.type='ArrowFunctionExpression'][arguments.1.async=true]:has(AwaitExpression > ImportExpression)",
+					message:
+						'Banned: vi.mock(..., async () => { await import(...) }) causes a birpc teardown race in browser-mode specs — see ADR 012. Use a synchronous factory + vi.hoisted instead.'
+				}
+			]
+		}
+	},
 	{
 		plugins: { boundaries },
 		settings: {

frontend/package-lock.json

@@ -7,6 +7,7 @@
 		"": {
 			"name": "frontend",
 			"version": "0.0.1",
+			"hasInstallScript": true,
 			"dependencies": {
 				"@tiptap/core": "3.22.5",
 				"@tiptap/extension-mention": "3.22.5",
@@ -40,6 +41,7 @@
 				"eslint-plugin-svelte": "^3.13.0",
 				"globals": "^16.5.0",
 				"openapi-typescript": "^7.8.0",
+				"patch-package": "^8.0.0",
 				"playwright": "^1.56.1",
 				"prettier": "^3.6.2",
 				"prettier-plugin-svelte": "^3.4.0",
@@ -3939,6 +3941,13 @@
 				"url": "https://opencollective.com/vitest"
 			}
 		},
+		"node_modules/@yarnpkg/lockfile": {
+			"version": "1.1.0",
+			"resolved": "https://registry.npmjs.org/@yarnpkg/lockfile/-/lockfile-1.1.0.tgz",
+			"integrity": "sha512-GpSwvyXOcOOlV70vbnzjj4fW5xW/FdUF6nQEt1ENy7m4ZCczi1+/buVUPAqmGfqznsORNFzUMjctTIp8a9tuCQ==",
+			"dev": true,
+			"license": "BSD-2-Clause"
+		},
 		"node_modules/acorn": {
 			"version": "8.16.0",
 			"resolved": "https://registry.npmjs.org/acorn/-/acorn-8.16.0.tgz",
@@ -4185,6 +4194,56 @@
 				"node": "^6 || ^7 || ^8 || ^9 || ^10 || ^11 || ^12 || >=13.7"
 			}
 		},
+		"node_modules/call-bind": {
+			"version": "1.0.9",
+			"resolved": "https://registry.npmjs.org/call-bind/-/call-bind-1.0.9.tgz",
+			"integrity": "sha512-a/hy+pNsFUTR+Iz8TCJvXudKVLAnz/DyeSUo10I5yvFDQJBFU2s9uqQpoSrJlroHUKoKqzg+epxyP9lqFdzfBQ==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"call-bind-apply-helpers": "^1.0.2",
+				"es-define-property": "^1.0.1",
+				"get-intrinsic": "^1.3.0",
+				"set-function-length": "^1.2.2"
+			},
+			"engines": {
+				"node": ">= 0.4"
+			},
+			"funding": {
+				"url": "https://github.com/sponsors/ljharb"
+			}
+		},
+		"node_modules/call-bind-apply-helpers": {
+			"version": "1.0.2",
+			"resolved": "https://registry.npmjs.org/call-bind-apply-helpers/-/call-bind-apply-helpers-1.0.2.tgz",
+			"integrity": "sha512-Sp1ablJ0ivDkSzjcaJdxEunN5/XvksFJ2sMBFfq6x0ryhQV/2b/KwFe21cMpmHtPOSij8K99/wSfoEuTObmuMQ==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"es-errors": "^1.3.0",
+				"function-bind": "^1.1.2"
+			},
+			"engines": {
+				"node": ">= 0.4"
+			}
+		},
+		"node_modules/call-bound": {
+			"version": "1.0.4",
+			"resolved": "https://registry.npmjs.org/call-bound/-/call-bound-1.0.4.tgz",
+			"integrity": "sha512-+ys997U96po4Kx/ABpBCqhA9EuxJaQWDQg7295H4hBphv3IZg0boBKuwYpt4YXp6MZ5AmZQnU/tyMTlRpaSejg==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"call-bind-apply-helpers": "^1.0.2",
+				"get-intrinsic": "^1.3.0"
+			},
+			"engines": {
+				"node": ">= 0.4"
+			},
+			"funding": {
+				"url": "https://github.com/sponsors/ljharb"
+			}
+		},
 		"node_modules/callsites": {
 			"version": "3.1.0",
 			"resolved": "https://registry.npmjs.org/callsites/-/callsites-3.1.0.tgz",
@@ -4266,6 +4325,22 @@
 				"url": "https://paulmillr.com/funding/"
 			}
 		},
+		"node_modules/ci-info": {
+			"version": "3.9.0",
+			"resolved": "https://registry.npmjs.org/ci-info/-/ci-info-3.9.0.tgz",
+			"integrity": "sha512-NIxF55hv4nSqQswkAeiOi1r83xy8JldOFDTWiug55KBu9Jnblncd2U6ViHmYgHf01TPZS77NJBhBMKdWj9HQMQ==",
+			"dev": true,
+			"funding": [
+				{
+					"type": "github",
+					"url": "https://github.com/sponsors/sibiraj-s"
+				}
+			],
+			"license": "MIT",
+			"engines": {
+				"node": ">=8"
+			}
+		},
 		"node_modules/clsx": {
 			"version": "2.1.1",
 			"resolved": "https://registry.npmjs.org/clsx/-/clsx-2.1.1.tgz",
@@ -4478,6 +4553,24 @@
 				"node": ">=0.10.0"
 			}
 		},
+		"node_modules/define-data-property": {
+			"version": "1.1.4",
+			"resolved": "https://registry.npmjs.org/define-data-property/-/define-data-property-1.1.4.tgz",
+			"integrity": "sha512-rBMvIzlpA8v6E+SJZoo++HAYqsLrkg7MSfIinMPFhmkorw7X+dOXVJQs+QT69zGkzMyfDnIMN2Wid1+NbL3T+A==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"es-define-property": "^1.0.0",
+				"es-errors": "^1.3.0",
+				"gopd": "^1.0.1"
+			},
+			"engines": {
+				"node": ">= 0.4"
+			},
+			"funding": {
+				"url": "https://github.com/sponsors/ljharb"
+			}
+		},
 		"node_modules/detect-libc": {
 			"version": "2.1.2",
 			"resolved": "https://registry.npmjs.org/detect-libc/-/detect-libc-2.1.2.tgz",
@@ -4513,6 +4606,21 @@
 				"@types/trusted-types": "^2.0.7"
 			}
 		},
+		"node_modules/dunder-proto": {
+			"version": "1.0.1",
+			"resolved": "https://registry.npmjs.org/dunder-proto/-/dunder-proto-1.0.1.tgz",
+			"integrity": "sha512-KIN/nDJBQRcXw0MLVhZE9iQHmG68qAVIBg9CqmUYjmQIhgij9U5MFvrqkUL5FbtyyzZuOeOt0zdeRe4UY7ct+A==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"call-bind-apply-helpers": "^1.0.1",
+				"es-errors": "^1.3.0",
+				"gopd": "^1.2.0"
+			},
+			"engines": {
+				"node": ">= 0.4"
+			}
+		},
 		"node_modules/electron-to-chromium": {
 			"version": "1.5.353",
 			"resolved": "https://registry.npmjs.org/electron-to-chromium/-/electron-to-chromium-1.5.353.tgz",
@@ -4546,6 +4654,26 @@
 				"url": "https://github.com/fb55/entities?sponsor=1"
 			}
 		},
+		"node_modules/es-define-property": {
+			"version": "1.0.1",
+			"resolved": "https://registry.npmjs.org/es-define-property/-/es-define-property-1.0.1.tgz",
+			"integrity": "sha512-e3nRfgfUZ4rNGL232gUgX06QNyyez04KdjFrF+LTRoOXmrOgFKDg4BCdsjW8EnT69eqdYGmRpJwiPVYNrCaW3g==",
+			"dev": true,
+			"license": "MIT",
+			"engines": {
+				"node": ">= 0.4"
+			}
+		},
+		"node_modules/es-errors": {
+			"version": "1.3.0",
+			"resolved": "https://registry.npmjs.org/es-errors/-/es-errors-1.3.0.tgz",
+			"integrity": "sha512-Zf5H2Kxt2xjTvbJvP2ZWLEICxA6j+hAmMzIlypy4xcBg1vKVnx89Wy0GbS+kf5cwCVFFzdCFh2XSCFNULS6csw==",
+			"dev": true,
+			"license": "MIT",
+			"engines": {
+				"node": ">= 0.4"
+			}
+		},
 		"node_modules/es-module-lexer": {
 			"version": "2.0.0",
 			"resolved": "https://registry.npmjs.org/es-module-lexer/-/es-module-lexer-2.0.0.tgz",
@@ -4553,6 +4681,19 @@
 			"dev": true,
 			"license": "MIT"
 		},
+		"node_modules/es-object-atoms": {
+			"version": "1.1.1",
+			"resolved": "https://registry.npmjs.org/es-object-atoms/-/es-object-atoms-1.1.1.tgz",
+			"integrity": "sha512-FGgH2h8zKNim9ljj7dankFPcICIK9Cp5bm+c2gQSYePhpaG5+esrLODihIorn+Pe6FGJzWhXQotPv73jTaldXA==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"es-errors": "^1.3.0"
+			},
+			"engines": {
+				"node": ">= 0.4"
+			}
+		},
 		"node_modules/esbuild": {
 			"version": "0.27.4",
 			"resolved": "https://registry.npmjs.org/esbuild/-/esbuild-0.27.4.tgz",
@@ -5084,6 +5225,16 @@
 				"url": "https://github.com/sponsors/sindresorhus"
 			}
 		},
+		"node_modules/find-yarn-workspace-root": {
+			"version": "2.0.0",
+			"resolved": "https://registry.npmjs.org/find-yarn-workspace-root/-/find-yarn-workspace-root-2.0.0.tgz",
+			"integrity": "sha512-1IMnbjt4KzsQfnhnzNd8wUEgXZ44IzZaZmnLYx7D5FZlaHt2gW20Cri8Q+E/t5tIj4+epTBub+2Zxu/vNILzqQ==",
+			"dev": true,
+			"license": "Apache-2.0",
+			"dependencies": {
+				"micromatch": "^4.0.2"
+			}
+		},
 		"node_modules/flat-cache": {
 			"version": "4.0.1",
 			"resolved": "https://registry.npmjs.org/flat-cache/-/flat-cache-4.0.1.tgz",
@@ -5105,6 +5256,21 @@
 			"dev": true,
 			"license": "ISC"
 		},
+		"node_modules/fs-extra": {
+			"version": "10.1.0",
+			"resolved": "https://registry.npmjs.org/fs-extra/-/fs-extra-10.1.0.tgz",
+			"integrity": "sha512-oRXApq54ETRj4eMiFzGnHWGy+zo5raudjuxN0b8H7s/RU2oW0Wvsx9O0ACRN/kRq9E8Vu/ReskGB5o3ji+FzHQ==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"graceful-fs": "^4.2.0",
+				"jsonfile": "^6.0.1",
+				"universalify": "^2.0.0"
+			},
+			"engines": {
+				"node": ">=12"
+			}
+		},
 		"node_modules/fsevents": {
 			"version": "2.3.2",
 			"resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.2.tgz",
@@ -5140,6 +5306,45 @@
 				"node": ">=6.9.0"
 			}
 		},
+		"node_modules/get-intrinsic": {
+			"version": "1.3.0",
+			"resolved": "https://registry.npmjs.org/get-intrinsic/-/get-intrinsic-1.3.0.tgz",
+			"integrity": "sha512-9fSjSaos/fRIVIp+xSJlE6lfwhES7LNtKaCBIamHsjr2na1BiABJPo0mOjjz8GJDURarmCPGqaiVg5mfjb98CQ==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"call-bind-apply-helpers": "^1.0.2",
+				"es-define-property": "^1.0.1",
+				"es-errors": "^1.3.0",
+				"es-object-atoms": "^1.1.1",
+				"function-bind": "^1.1.2",
+				"get-proto": "^1.0.1",
+				"gopd": "^1.2.0",
+				"has-symbols": "^1.1.0",
+				"hasown": "^2.0.2",
+				"math-intrinsics": "^1.1.0"
+			},
+			"engines": {
+				"node": ">= 0.4"
+			},
+			"funding": {
+				"url": "https://github.com/sponsors/ljharb"
+			}
+		},
+		"node_modules/get-proto": {
+			"version": "1.0.1",
+			"resolved": "https://registry.npmjs.org/get-proto/-/get-proto-1.0.1.tgz",
+			"integrity": "sha512-sTSfBjoXBp89JvIKIefqw7U2CCebsc74kiY6awiGogKtoSGbgjYE/G/+l9sF3MWFPNc9IcoOC4ODfKHfxFmp0g==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"dunder-proto": "^1.0.1",
+				"es-object-atoms": "^1.0.0"
+			},
+			"engines": {
+				"node": ">= 0.4"
+			}
+		},
 		"node_modules/get-tsconfig": {
 			"version": "4.14.0",
 			"resolved": "https://registry.npmjs.org/get-tsconfig/-/get-tsconfig-4.14.0.tgz",
@@ -5179,6 +5384,19 @@
 				"url": "https://github.com/sponsors/sindresorhus"
 			}
 		},
+		"node_modules/gopd": {
+			"version": "1.2.0",
+			"resolved": "https://registry.npmjs.org/gopd/-/gopd-1.2.0.tgz",
+			"integrity": "sha512-ZUKRh6/kUFoAiTAtTYPZJ3hw9wNxx+BIBOijnlG9PnrJsCcSjs1wyyD6vJpaYtgnzDrKYRSqf3OO6Rfa93xsRg==",
+			"dev": true,
+			"license": "MIT",
+			"engines": {
+				"node": ">= 0.4"
+			},
+			"funding": {
+				"url": "https://github.com/sponsors/ljharb"
+			}
+		},
 		"node_modules/graceful-fs": {
 			"version": "4.2.11",
 			"resolved": "https://registry.npmjs.org/graceful-fs/-/graceful-fs-4.2.11.tgz",
@@ -5218,6 +5436,32 @@
 				"node": ">=8"
 			}
 		},
+		"node_modules/has-property-descriptors": {
+			"version": "1.0.2",
+			"resolved": "https://registry.npmjs.org/has-property-descriptors/-/has-property-descriptors-1.0.2.tgz",
+			"integrity": "sha512-55JNKuIW+vq4Ke1BjOTjM2YctQIvCT7GFzHwmfZPGo5wnrgkid0YQtnAleFSqumZm4az3n2BS+erby5ipJdgrg==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"es-define-property": "^1.0.0"
+			},
+			"funding": {
+				"url": "https://github.com/sponsors/ljharb"
+			}
+		},
+		"node_modules/has-symbols": {
+			"version": "1.1.0",
+			"resolved": "https://registry.npmjs.org/has-symbols/-/has-symbols-1.1.0.tgz",
+			"integrity": "sha512-1cDNdwJ2Jaohmb3sg4OmKaMBwuC48sYni5HUw2DvsC8LjGTLK9h+eb1X6RyuOHe4hT0ULCW68iomhjUoKUqlPQ==",
+			"dev": true,
+			"license": "MIT",
+			"engines": {
+				"node": ">= 0.4"
+			},
+			"funding": {
+				"url": "https://github.com/sponsors/ljharb"
+			}
+		},
 		"node_modules/hasown": {
 			"version": "2.0.2",
 			"resolved": "https://registry.npmjs.org/hasown/-/hasown-2.0.2.tgz",
@@ -5350,6 +5594,22 @@
 				"url": "https://github.com/sponsors/ljharb"
 			}
 		},
+		"node_modules/is-docker": {
+			"version": "2.2.1",
+			"resolved": "https://registry.npmjs.org/is-docker/-/is-docker-2.2.1.tgz",
+			"integrity": "sha512-F+i2BKsFrH66iaUFc0woD8sLy8getkwTwtOBjvs56Cx4CgJDeKQeqfz8wAYiSb8JOprWhHH5p77PbmYCvvUuXQ==",
+			"dev": true,
+			"license": "MIT",
+			"bin": {
+				"is-docker": "cli.js"
+			},
+			"engines": {
+				"node": ">=8"
+			},
+			"funding": {
+				"url": "https://github.com/sponsors/sindresorhus"
+			}
+		},
 		"node_modules/is-extglob": {
 			"version": "2.1.1",
 			"resolved": "https://registry.npmjs.org/is-extglob/-/is-extglob-2.1.1.tgz",
@@ -5406,6 +5666,26 @@
 				"@types/estree": "*"
 			}
 		},
+		"node_modules/is-wsl": {
+			"version": "2.2.0",
+			"resolved": "https://registry.npmjs.org/is-wsl/-/is-wsl-2.2.0.tgz",
+			"integrity": "sha512-fKzAra0rGJUUBwGBgNkHZuToZcn+TtXHpeCgmkMJMMYx1sQDYaCSyjJBSCa2nH1DGm7s3n1oBnohoVTBaN7Lww==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"is-docker": "^2.0.0"
+			},
+			"engines": {
+				"node": ">=8"
+			}
+		},
+		"node_modules/isarray": {
+			"version": "2.0.5",
+			"resolved": "https://registry.npmjs.org/isarray/-/isarray-2.0.5.tgz",
+			"integrity": "sha512-xHjhDr3cNBK0BzdUJSPXZntQUx/mwMS5Rw4A7lPJ90XGAO6ISP/ePDNuo0vhqOZU+UD5JoodwCAAoZQd3FeAKw==",
+			"dev": true,
+			"license": "MIT"
+		},
 		"node_modules/isexe": {
 			"version": "2.0.0",
 			"resolved": "https://registry.npmjs.org/isexe/-/isexe-2.0.0.tgz",
@@ -5579,6 +5859,26 @@
 			"dev": true,
 			"license": "MIT"
 		},
+		"node_modules/json-stable-stringify": {
+			"version": "1.3.0",
+			"resolved": "https://registry.npmjs.org/json-stable-stringify/-/json-stable-stringify-1.3.0.tgz",
+			"integrity": "sha512-qtYiSSFlwot9XHtF9bD9c7rwKjr+RecWT//ZnPvSmEjpV5mmPOCN4j8UjY5hbjNkOwZ/jQv3J6R1/pL7RwgMsg==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"call-bind": "^1.0.8",
+				"call-bound": "^1.0.4",
+				"isarray": "^2.0.5",
+				"jsonify": "^0.0.1",
+				"object-keys": "^1.1.1"
+			},
+			"engines": {
+				"node": ">= 0.4"
+			},
+			"funding": {
+				"url": "https://github.com/sponsors/ljharb"
+			}
+		},
 		"node_modules/json-stable-stringify-without-jsonify": {
 			"version": "1.0.1",
 			"resolved": "https://registry.npmjs.org/json-stable-stringify-without-jsonify/-/json-stable-stringify-without-jsonify-1.0.1.tgz",
@@ -5599,6 +5899,29 @@
 				"node": ">=6"
 			}
 		},
+		"node_modules/jsonfile": {
+			"version": "6.2.1",
+			"resolved": "https://registry.npmjs.org/jsonfile/-/jsonfile-6.2.1.tgz",
+			"integrity": "sha512-zwOTdL3rFQ/lRdBnntKVOX6k5cKJwEc1HdilT71BWEu7J41gXIB2MRp+vxduPSwZJPWBxEzv4yH1wYLJGUHX4Q==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"universalify": "^2.0.0"
+			},
+			"optionalDependencies": {
+				"graceful-fs": "^4.1.6"
+			}
+		},
+		"node_modules/jsonify": {
+			"version": "0.0.1",
+			"resolved": "https://registry.npmjs.org/jsonify/-/jsonify-0.0.1.tgz",
+			"integrity": "sha512-2/Ki0GcmuqSrgFyelQq9M05y7PS0mEwuIzrf3f1fPqkVDVRvZrPZtVSMHxdgo8Aq0sxAOb/cr2aqqA3LeWHVPg==",
+			"dev": true,
+			"license": "Public Domain",
+			"funding": {
+				"url": "https://github.com/sponsors/ljharb"
+			}
+		},
 		"node_modules/keyv": {
 			"version": "4.5.4",
 			"resolved": "https://registry.npmjs.org/keyv/-/keyv-4.5.4.tgz",
@@ -5609,6 +5932,16 @@
 				"json-buffer": "3.0.1"
 			}
 		},
+		"node_modules/klaw-sync": {
+			"version": "6.0.0",
+			"resolved": "https://registry.npmjs.org/klaw-sync/-/klaw-sync-6.0.0.tgz",
+			"integrity": "sha512-nIeuVSzdCCs6TDPTqI8w1Yre34sSq7AkZ4B3sfOBbI2CgVSB4Du4aLQijFU2+lhAFCwt9+42Hel6lQNIv6AntQ==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"graceful-fs": "^4.1.11"
+			}
+		},
 		"node_modules/kleur": {
 			"version": "4.1.5",
 			"resolved": "https://registry.npmjs.org/kleur/-/kleur-4.1.5.tgz",
@@ -6004,6 +6337,16 @@
 				"url": "https://github.com/sponsors/sindresorhus"
 			}
 		},
+		"node_modules/math-intrinsics": {
+			"version": "1.1.0",
+			"resolved": "https://registry.npmjs.org/math-intrinsics/-/math-intrinsics-1.1.0.tgz",
+			"integrity": "sha512-/IXtbwEk5HTPyEwyKX6hGkYXxM9nbj64B+ilVJnC/R6B0pH5G4V3b0pVbL7DBj4tkhBAppbQUlf6F6Xl9LHu1g==",
+			"dev": true,
+			"license": "MIT",
+			"engines": {
+				"node": ">= 0.4"
+			}
+		},
 		"node_modules/mdn-data": {
 			"version": "2.27.1",
 			"resolved": "https://registry.npmjs.org/mdn-data/-/mdn-data-2.27.1.tgz",
@@ -6160,6 +6503,16 @@
 			"dev": true,
 			"license": "MIT"
 		},
+		"node_modules/object-keys": {
+			"version": "1.1.1",
+			"resolved": "https://registry.npmjs.org/object-keys/-/object-keys-1.1.1.tgz",
+			"integrity": "sha512-NuAESUOUMrlIXOfHKzD6bpPu3tYt3xvjNdRIQ+FeT0lNb4K8WR70CaDxhuNguS2XG+GjkyMwOzsN5ZktImfhLA==",
+			"dev": true,
+			"license": "MIT",
+			"engines": {
+				"node": ">= 0.4"
+			}
+		},
 		"node_modules/obug": {
 			"version": "2.1.1",
 			"resolved": "https://registry.npmjs.org/obug/-/obug-2.1.1.tgz",
@@ -6171,6 +6524,23 @@
 			],
 			"license": "MIT"
 		},
+		"node_modules/open": {
+			"version": "7.4.2",
+			"resolved": "https://registry.npmjs.org/open/-/open-7.4.2.tgz",
+			"integrity": "sha512-MVHddDVweXZF3awtlAS+6pgKLlm/JgxZ90+/NBurBoQctVOOB/zDdVjcyPzQ+0laDGbsWgrRkflI65sQeOgT9Q==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"is-docker": "^2.0.0",
+				"is-wsl": "^2.1.1"
+			},
+			"engines": {
+				"node": ">=8"
+			},
+			"funding": {
+				"url": "https://github.com/sponsors/sindresorhus"
+			}
+		},
 		"node_modules/openapi-fetch": {
 			"version": "0.13.8",
 			"resolved": "https://registry.npmjs.org/openapi-fetch/-/openapi-fetch-0.13.8.tgz",
@@ -6319,6 +6689,36 @@
 				"url": "https://github.com/inikulin/parse5?sponsor=1"
 			}
 		},
+		"node_modules/patch-package": {
+			"version": "8.0.1",
+			"resolved": "https://registry.npmjs.org/patch-package/-/patch-package-8.0.1.tgz",
+			"integrity": "sha512-VsKRIA8f5uqHQ7NGhwIna6Bx6D9s/1iXlA1hthBVBEbkq+t4kXD0HHt+rJhf/Z+Ci0F/HCB2hvn0qLdLG+Qxlw==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"@yarnpkg/lockfile": "^1.1.0",
+				"chalk": "^4.1.2",
+				"ci-info": "^3.7.0",
+				"cross-spawn": "^7.0.3",
+				"find-yarn-workspace-root": "^2.0.0",
+				"fs-extra": "^10.0.0",
+				"json-stable-stringify": "^1.0.2",
+				"klaw-sync": "^6.0.0",
+				"minimist": "^1.2.6",
+				"open": "^7.4.2",
+				"semver": "^7.5.3",
+				"slash": "^2.0.0",
+				"tmp": "^0.2.4",
+				"yaml": "^2.2.2"
+			},
+			"bin": {
+				"patch-package": "index.js"
+			},
+			"engines": {
+				"node": ">=14",
+				"npm": ">5"
+			}
+		},
 		"node_modules/path-exists": {
 			"version": "4.0.0",
 			"resolved": "https://registry.npmjs.org/path-exists/-/path-exists-4.0.0.tgz",
@@ -6989,6 +7389,24 @@
 			"dev": true,
 			"license": "MIT"
 		},
+		"node_modules/set-function-length": {
+			"version": "1.2.2",
+			"resolved": "https://registry.npmjs.org/set-function-length/-/set-function-length-1.2.2.tgz",
+			"integrity": "sha512-pgRc4hJ4/sNjWCSS9AmnS40x3bNMDTknHgL5UaMBTMyJnU90EgWh1Rz+MC9eFu4BuN/UwZjKQuY/1v3rM7HMfg==",
+			"dev": true,
+			"license": "MIT",
+			"dependencies": {
+				"define-data-property": "^1.1.4",
+				"es-errors": "^1.3.0",
+				"function-bind": "^1.1.2",
+				"get-intrinsic": "^1.2.4",
+				"gopd": "^1.0.1",
+				"has-property-descriptors": "^1.0.2"
+			},
+			"engines": {
+				"node": ">= 0.4"
+			}
+		},
 		"node_modules/shebang-command": {
 			"version": "2.0.0",
 			"resolved": "https://registry.npmjs.org/shebang-command/-/shebang-command-2.0.0.tgz",
@@ -7034,6 +7452,16 @@
 				"node": ">=18"
 			}
 		},
+		"node_modules/slash": {
+			"version": "2.0.0",
+			"resolved": "https://registry.npmjs.org/slash/-/slash-2.0.0.tgz",
+			"integrity": "sha512-ZYKh3Wh2z1PpEXWr0MpSBZ0V6mZHAQfYevttO11c51CaWjGTaadiKZ+wVt1PbMlDV5qhMFslpZCemhwOK7C89A==",
+			"dev": true,
+			"license": "MIT",
+			"engines": {
+				"node": ">=6"
+			}
+		},
 		"node_modules/source-map": {
 			"version": "0.6.1",
 			"resolved": "https://registry.npmjs.org/source-map/-/source-map-0.6.1.tgz",
@@ -7324,6 +7752,16 @@
 			"integrity": "sha512-uiHN8PIB1VmWyS98eZYja4xzlYqeFZVjb4OuYlJQnZAuJhMw4PbKQOKgHKhBdJR3FE/t5mUQ1Kd80++B+qhD1Q==",
 			"license": "MIT"
 		},
+		"node_modules/tmp": {
+			"version": "0.2.5",
+			"resolved": "https://registry.npmjs.org/tmp/-/tmp-0.2.5.tgz",
+			"integrity": "sha512-voyz6MApa1rQGUxT3E+BK7/ROe8itEx7vD8/HEvt4xwXucvQ5G5oeEiHkmHZJuBO21RpOf+YYm9MOivj709jow==",
+			"dev": true,
+			"license": "MIT",
+			"engines": {
+				"node": ">=14.14"
+			}
+		},
 		"node_modules/to-regex-range": {
 			"version": "5.0.1",
 			"resolved": "https://registry.npmjs.org/to-regex-range/-/to-regex-range-5.0.1.tgz",
@@ -7486,6 +7924,16 @@
 			"dev": true,
 			"license": "MIT"
 		},
+		"node_modules/universalify": {
+			"version": "2.0.1",
+			"resolved": "https://registry.npmjs.org/universalify/-/universalify-2.0.1.tgz",
+			"integrity": "sha512-gptHNQghINnc/vTGIk0SOFGFNXw7JVrlRUtConJRlvaw6DuX0wO5Jeko9sWrMBhh+PsYAZ7oXAiOnf/UKogyiw==",
+			"dev": true,
+			"license": "MIT",
+			"engines": {
+				"node": ">= 10.0.0"
+			}
+		},
 		"node_modules/unplugin": {
 			"version": "2.3.11",
 			"resolved": "https://registry.npmjs.org/unplugin/-/unplugin-2.3.11.tgz",
@@ -8001,6 +8449,22 @@
 			"dev": true,
 			"license": "ISC"
 		},
+		"node_modules/yaml": {
+			"version": "2.9.0",
+			"resolved": "https://registry.npmjs.org/yaml/-/yaml-2.9.0.tgz",
+			"integrity": "sha512-2AvhNX3mb8zd6Zy7INTtSpl1F15HW6Wnqj0srWlkKLcpYl/gMIMJiyuGq2KeI2YFxUPjdlB+3Lc10seMLtL4cA==",
+			"dev": true,
+			"license": "ISC",
+			"bin": {
+				"yaml": "bin.mjs"
+			},
+			"engines": {
+				"node": ">= 14.6"
+			},
+			"funding": {
+				"url": "https://github.com/sponsors/eemeli"
+			}
+		},
 		"node_modules/yaml-ast-parser": {
 			"version": "0.0.43",
 			"resolved": "https://registry.npmjs.org/yaml-ast-parser/-/yaml-ast-parser-0.0.43.tgz",

frontend/package.json

@@ -8,6 +8,7 @@
 		"build": "vite build",
 		"preview": "vite preview",
 		"prepare": "svelte-kit sync || true && git -C .. config core.hooksPath .husky 2>/dev/null || true",
+		"postinstall": "patch-package",
 		"check": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json",
 		"check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch",
 		"format": "prettier --write .",
@@ -54,6 +55,7 @@
 		"eslint-plugin-svelte": "^3.13.0",
 		"globals": "^16.5.0",
 		"openapi-typescript": "^7.8.0",
+		"patch-package": "^8.0.0",
 		"playwright": "^1.56.1",
 		"prettier": "^3.6.2",
 		"prettier-plugin-svelte": "^3.4.0",

frontend/patches/@vitest+browser-playwright+4.1.0.patch

@@ -0,0 +1,62 @@
+diff --git a/node_modules/@vitest/browser-playwright/dist/index.js b/node_modules/@vitest/browser-playwright/dist/index.js
+index 5d0d37b..821d7b4 100644
+--- a/node_modules/@vitest/browser-playwright/dist/index.js
++++ b/node_modules/@vitest/browser-playwright/dist/index.js
+@@ -935,7 +935,7 @@ class PlaywrightBrowserProvider {
+ 	createMocker() {
+ 		const idPreficates = new Map();
+ 		const sessionIds = new Map();
+-		function createPredicate(sessionId, url) {
++		function createPredicate(url) {
+ 			const moduleUrl = new URL(url, "http://localhost");
+ 			const predicate = (url) => {
+ 				if (url.searchParams.has("_vitest_original")) {
+@@ -960,11 +960,7 @@ class PlaywrightBrowserProvider {
+ 				}
+ 				return true;
+ 			};
+-			const ids = sessionIds.get(sessionId) || [];
+-			ids.push(moduleUrl.href);
+-			sessionIds.set(sessionId, ids);
+-			idPreficates.set(predicateKey(sessionId, moduleUrl.href), predicate);
+-			return predicate;
++			return { url: moduleUrl.href, predicate };
+ 		}
+ 		function predicateKey(sessionId, url) {
+ 			return `${sessionId}:${url}`;
+@@ -972,7 +968,23 @@ class PlaywrightBrowserProvider {
+ 		return {
+ 			register: async (sessionId, module) => {
+ 				const page = this.getPage(sessionId);
+-				await page.context().route(createPredicate(sessionId, module.url), async (route) => {
++				const { url: moduleUrl, predicate } = createPredicate(module.url);
++				const key = predicateKey(sessionId, moduleUrl);
++				// Backport of vitest PR #10267: if a route handler is already
++				// registered for this resolved module URL in this session,
++				// unroute it before installing the new one. Without this guard,
++				// duplicate-id mocks (e.g. '$lib/foo.svelte' + '$lib/foo.svelte.js')
++				// leak an orphan route whose handler crashes after the next
++				// session's birpc channel closes.
++				const existingPredicate = idPreficates.get(key);
++				if (existingPredicate) {
++					await page.context().unroute(existingPredicate);
++				}
++				const ids = sessionIds.get(sessionId) ?? new Set();
++				ids.add(moduleUrl);
++				sessionIds.set(sessionId, ids);
++				idPreficates.set(key, predicate);
++				await page.context().route(predicate, async (route) => {
+ 					if (module.type === "manual") {
+ 						const exports$1 = Object.keys(await module.resolve());
+ 						const body = createManualModuleSource(module.url, exports$1);
+@@ -1033,8 +1045,8 @@ class PlaywrightBrowserProvider {
+ 			},
+ 			clear: async (sessionId) => {
+ 				const page = this.getPage(sessionId);
+-				const ids = sessionIds.get(sessionId) || [];
+-				const promises = ids.map((id) => {
++				const ids = sessionIds.get(sessionId) ?? new Set();
++				const promises = [...ids].map((id) => {
+ 					const key = predicateKey(sessionId, id);
+ 					const predicate = idPreficates.get(key);
+ 					if (predicate) {

frontend/src/__meta__/browser-preload-disabled.svelte.test.ts

@@ -0,0 +1,20 @@
+import { describe, it, expect } from 'vitest';
+
+// Browser-mode tests must run with SvelteKit's hover-prefetch disabled.
+// Hover-prefetch fires real `fetch` requests for the target route's loader
+// chunks; those go through the same Playwright route handler that serves
+// mocked modules. Even after `cleanup()` tears down the iframe, an in-flight
+// prefetch can still hit the handler — and if the worker's birpc channel has
+// closed by then, the handler raises an unhandled rejection. ADR-012 / #553.
+//
+// This test enforces that the test-setup file ran and switched preload-data
+// off on `document.body` before any spec started rendering.
+describe('browser test setup', () => {
+	it('disables SvelteKit loader-data prefetch on document.body', () => {
+		expect(document.body.dataset.sveltekitPreloadData).toBe('off');
+	});
+
+	it('disables SvelteKit route-code prefetch on document.body', () => {
+		expect(document.body.dataset.sveltekitPreloadCode).toBe('off');
+	});
+});

frontend/src/__meta__/no-async-mock-factories.test.ts

@@ -0,0 +1,82 @@
+import { describe, it, expect } from 'vitest';
+import { readdirSync, readFileSync } from 'fs';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+// Belt-and-braces detector for the birpc teardown race named in ADR-012 / #553.
+// ESLint catches the pattern at save time, CI grep catches it before the test
+// suite launches, and this in-suite test catches it at every vitest invocation —
+// the layer hardest to disable or scope around.
+//
+// We scan source text rather than parsing AST: fast, no parser dependency,
+// good enough for the named anti-pattern. The pattern matches
+// `vi.mock(<arg>, async ... { ... await import(...) ... })`.
+
+const ASYNC_MOCK_WITH_DYNAMIC_IMPORT = /vi\.mock\([^)]*,\s*async[^{]*\{[\s\S]*?await\s+import\s*\(/;
+
+export function hasAsyncMockFactoryWithDynamicImport(source: string): boolean {
+	return ASYNC_MOCK_WITH_DYNAMIC_IMPORT.test(source);
+}
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const SRC_ROOT = path.resolve(__dirname, '..');
+
+function findBrowserSpecs(): string[] {
+	const entries = readdirSync(SRC_ROOT, { recursive: true, withFileTypes: true });
+	return entries
+		.filter(
+			(e) =>
+				e.isFile() && (e.name.endsWith('.svelte.test.ts') || e.name.endsWith('.svelte.spec.ts'))
+		)
+		.map((e) => path.join(e.parentPath ?? (e as { path: string }).path, e.name));
+}
+
+describe('scan: hasAsyncMockFactoryWithDynamicImport', () => {
+	it('flags async vi.mock factory with await import in body', () => {
+		const fixture = `vi.mock('$app/stores', async () => {
+			const mod = await import('./__mocks__/navigatingStore');
+			return { navigating: mod.navigatingStore };
+		});`;
+		expect(hasAsyncMockFactoryWithDynamicImport(fixture)).toBe(true);
+	});
+
+	it('does not flag sync vi.mock factory', () => {
+		const fixture = `vi.mock('$app/state', () => ({ navigating: { type: null } }));`;
+		expect(hasAsyncMockFactoryWithDynamicImport(fixture)).toBe(false);
+	});
+
+	it('does not flag async vi.mock factory without dynamic import', () => {
+		const fixture = `vi.mock('foo', async () => {
+			const x = await Promise.resolve(42);
+			return { bar: x };
+		});`;
+		expect(hasAsyncMockFactoryWithDynamicImport(fixture)).toBe(false);
+	});
+
+	it('does not flag dynamic import outside any vi.mock', () => {
+		const fixture = `async function load() {
+			const mod = await import('./something');
+			return mod.default;
+		}`;
+		expect(hasAsyncMockFactoryWithDynamicImport(fixture)).toBe(false);
+	});
+
+	it('flags async factory written as async function expression', () => {
+		const fixture = `vi.mock('foo', async function () {
+			const mod = await import('./bar');
+			return mod;
+		});`;
+		expect(hasAsyncMockFactoryWithDynamicImport(fixture)).toBe(true);
+	});
+});
+
+describe('browser specs: no async vi.mock factory contains await import', () => {
+	it('every src/**/*.svelte.{test,spec}.ts file is clean', () => {
+		const specFiles = findBrowserSpecs();
+		expect(specFiles.length).toBeGreaterThan(0);
+		const offenders = specFiles.filter((file) =>
+			hasAsyncMockFactoryWithDynamicImport(readFileSync(file, 'utf-8'))
+		);
+		expect(offenders).toEqual([]);
+	});
+});

frontend/src/__meta__/no-duplicate-mock-ids.test.ts

@@ -0,0 +1,130 @@
+import { describe, it, expect } from 'vitest';
+import { readdirSync, readFileSync } from 'fs';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+// Belt-and-braces detector for the duplicate-id birpc race named in
+// ADR-012 / #553. When the same resolved module URL is mocked via two
+// distinct vi.mock id strings (e.g. '$lib/foo.svelte' and
+// '$lib/foo.svelte.js'), @vitest/browser-playwright registers two
+// Playwright routes against one cleanup slot — the orphan survives, fires
+// after the next session's birpc closes, and crashes the run with
+// "[birpc] rpc is closed, cannot call resolveManualMock".
+//
+// Fixed upstream in vitest PR #10267; until that fix reaches a published
+// release, normalisation in user-land is the practical guard. This test
+// catches the pattern at every vitest invocation — the layer hardest to
+// disable or scope around.
+
+const VI_MOCK_ID = /vi\.mock\(\s*['"]([^'"]+)['"]/g;
+
+function extractMockIds(source: string): string[] {
+	const ids: string[] = [];
+	for (const match of source.matchAll(VI_MOCK_ID)) {
+		ids.push(match[1]);
+	}
+	return ids;
+}
+
+function canonicalise(id: string): string {
+	if (id.endsWith('.svelte.js')) return id.slice(0, -3);
+	if (id.endsWith('.svelte.ts')) return id.slice(0, -3);
+	return id;
+}
+
+export function findDuplicateMockIds(
+	specSources: Record<string, string>
+): Map<string, Set<string>> {
+	const byCanonical = new Map<string, Set<string>>();
+	for (const source of Object.values(specSources)) {
+		for (const raw of extractMockIds(source)) {
+			const canonical = canonicalise(raw);
+			const existing = byCanonical.get(canonical) ?? new Set<string>();
+			existing.add(raw);
+			byCanonical.set(canonical, existing);
+		}
+	}
+	const duplicates = new Map<string, Set<string>>();
+	for (const [canonical, raws] of byCanonical) {
+		if (raws.size >= 2) duplicates.set(canonical, raws);
+	}
+	return duplicates;
+}
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const SRC_ROOT = path.resolve(__dirname, '..');
+
+function findBrowserSpecs(): string[] {
+	const entries = readdirSync(SRC_ROOT, { recursive: true, withFileTypes: true });
+	return entries
+		.filter(
+			(e) =>
+				e.isFile() && (e.name.endsWith('.svelte.test.ts') || e.name.endsWith('.svelte.spec.ts'))
+		)
+		.map((e) => path.join(e.parentPath ?? (e as { path: string }).path, e.name));
+}
+
+describe('scan: findDuplicateMockIds', () => {
+	it('flags two specs mocking the same module under .svelte and .svelte.js', () => {
+		const dup = findDuplicateMockIds({
+			'a.spec.ts': `vi.mock('$lib/foo.svelte', () => ({}));`,
+			'b.spec.ts': `vi.mock('$lib/foo.svelte.js', () => ({}));`
+		});
+		expect(dup.get('$lib/foo.svelte')).toEqual(new Set(['$lib/foo.svelte', '$lib/foo.svelte.js']));
+	});
+
+	it('does not flag two specs both using $lib/foo.svelte', () => {
+		const dup = findDuplicateMockIds({
+			'a.spec.ts': `vi.mock('$lib/foo.svelte', () => ({}));`,
+			'b.spec.ts': `vi.mock('$lib/foo.svelte', () => ({}));`
+		});
+		expect(dup.size).toBe(0);
+	});
+
+	it('does not flag $app/state and $app/stores (different modules)', () => {
+		const dup = findDuplicateMockIds({
+			'a.spec.ts': `vi.mock('$app/state', () => ({}));`,
+			'b.spec.ts': `vi.mock('$app/stores', () => ({}));`
+		});
+		expect(dup.size).toBe(0);
+	});
+
+	it('does not flag $lib/foo and $lib/bar (different canonical paths)', () => {
+		const dup = findDuplicateMockIds({
+			'a.spec.ts': `vi.mock('$lib/foo', () => ({}));`,
+			'b.spec.ts': `vi.mock('$lib/bar', () => ({}));`
+		});
+		expect(dup.size).toBe(0);
+	});
+
+	it('flags both spellings within a single file', () => {
+		const dup = findDuplicateMockIds({
+			'a.spec.ts': `
+				vi.mock('$lib/foo.svelte', () => ({}));
+				vi.mock('$lib/foo.svelte.js', () => ({}));
+			`
+		});
+		expect(dup.get('$lib/foo.svelte')?.size).toBe(2);
+	});
+
+	it('canonicalises .svelte.ts the same way as .svelte.js', () => {
+		const dup = findDuplicateMockIds({
+			'a.spec.ts': `vi.mock('$lib/foo.svelte', () => ({}));`,
+			'b.spec.ts': `vi.mock('$lib/foo.svelte.ts', () => ({}));`
+		});
+		expect(dup.get('$lib/foo.svelte')?.size).toBe(2);
+	});
+});
+
+describe('browser specs: no duplicate-id vi.mock calls across the suite', () => {
+	it('every mocked module is referenced under exactly one id string', () => {
+		const specFiles = findBrowserSpecs();
+		expect(specFiles.length).toBeGreaterThan(0);
+		const sources = Object.fromEntries(
+			specFiles.map((file) => [file, readFileSync(file, 'utf-8')])
+		);
+		const duplicates = findDuplicateMockIds(sources);
+		const report = Object.fromEntries([...duplicates].map(([k, v]) => [k, [...v]]));
+		expect(report).toEqual({});
+	});
+});

frontend/src/lib/activity/ChronikFuerDichBox.svelte

@@ -79,7 +79,7 @@ function href(n: NotificationItem): string {
 		<ul role="list" class="flex flex-col gap-2">
 			{#each unread as n (n.id)}
 				<li
-					class="fade-in group flex items-start gap-3 rounded-sm p-2 transition-colors hover:bg-canvas"
+					class="chronik-fade-in group flex items-start gap-3 rounded-sm p-2 transition-colors hover:bg-canvas"
 				>
 					<a
 						href={href(n)}
@@ -124,26 +124,3 @@ function href(n: NotificationItem): string {
 		</ul>
 	{/if}
 </section>
-
-<style>
-.fade-in {
-	animation: chronik-fade-in 160ms ease-out;
-}
-
-@keyframes chronik-fade-in {
-	from {
-		opacity: 0;
-		transform: translateY(-4px);
-	}
-	to {
-		opacity: 1;
-		transform: translateY(0);
-	}
-}
-
-@media (prefers-reduced-motion: reduce) {
-	.fade-in {
-		animation: none;
-	}
-}
-</style>

frontend/src/lib/document/EnrichmentBlock.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-import { navigating } from '$app/stores';
+import { navigating } from '$app/state';
 import DashboardNeedsMetadata from './DashboardNeedsMetadata.svelte';
 import UploadSuccessBanner from './UploadSuccessBanner.svelte';
 
@@ -18,7 +18,7 @@ interface Props {
 
 let { topDocs, totalCount, bannerCount, onBannerClose }: Props = $props();
 
-const showSkeleton = $derived(!!$navigating && topDocs.length === 0);
+const showSkeleton = $derived(!!navigating.type && topDocs.length === 0);
 const showBlock = $derived(topDocs.length > 0 || bannerCount > 0 || showSkeleton);
 </script>
 

frontend/src/lib/document/EnrichmentBlock.svelte.spec.ts

@@ -2,19 +2,23 @@ import { describe, it, expect, afterEach, vi } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page } from 'vitest/browser';
 
-// The store must live in a separate module because vi.mock factories are
-// hoisted and cannot reference top-level variables defined in this file.
-import { navigatingStore } from './__mocks__/navigatingStore';
 import EnrichmentBlock from './EnrichmentBlock.svelte';
 
-vi.mock('$app/stores', async () => {
-	const mod = await import('./__mocks__/navigatingStore');
-	return { navigating: mod.navigatingStore };
-});
+// Hoist the mutable navigation reference so vi.mock's factory (also hoisted)
+// can read it via a getter. Sync factory, no dynamic import: ADR-012 invariant.
+const { mockNavigating } = vi.hoisted(() => ({
+	mockNavigating: { type: null as string | null }
+}));
+
+vi.mock('$app/state', () => ({
+	get navigating() {
+		return mockNavigating;
+	}
+}));
 
 afterEach(() => {
 	cleanup();
-	navigatingStore.set(null);
+	mockNavigating.type = null;
 });
 
 type Doc = { id: string; title: string; uploadedAt: string };
@@ -65,8 +69,8 @@ describe('EnrichmentBlock', () => {
 		await expect.element(page.getByTestId('dashboard-needs-metadata')).toBeInTheDocument();
 	});
 
-	it('renders the skeleton when $navigating is active and topDocs is empty', async () => {
-		navigatingStore.set({ type: 'link' });
+	it('renders the skeleton when navigation is active and topDocs is empty', async () => {
+		mockNavigating.type = 'link';
 		render(EnrichmentBlock, {
 			topDocs: [],
 			totalCount: 0,
@@ -76,8 +80,8 @@ describe('EnrichmentBlock', () => {
 		await expect.element(page.getByTestId('enrichment-block-skeleton')).toBeInTheDocument();
 	});
 
-	it('does not render the skeleton when topDocs is non-empty even during $navigating', async () => {
-		navigatingStore.set({ type: 'link' });
+	it('does not render the skeleton when topDocs is non-empty even during navigation', async () => {
+		mockNavigating.type = 'link';
 		render(EnrichmentBlock, {
 			topDocs: [doc('d1')],
 			totalCount: 1,

frontend/src/lib/document/__mocks__/navigatingStore.ts

@@ -1,3 +0,0 @@
-import { writable } from 'svelte/store';
-
-export const navigatingStore = writable<unknown | null>(null);

frontend/src/lib/document/annotation/AnnotationLayer.svelte.spec.ts

@@ -107,7 +107,7 @@ describe('AnnotationLayer', () => {
 		});
 
 		await expect.element(page.getByTestId('annotation-ann-1')).toBeInTheDocument();
-		expect(page.getByTestId('annotation-delete-ann-1').query()).toBeNull();
+		await expect.element(page.getByTestId('annotation-delete-ann-1')).not.toBeInTheDocument();
 	});
 
 	it('does not show delete button when canDraw is false even if annotation is active', async () => {
@@ -120,6 +120,6 @@ describe('AnnotationLayer', () => {
 		});
 
 		await expect.element(page.getByTestId('annotation-ann-1')).toBeInTheDocument();
-		expect(page.getByTestId('annotation-delete-ann-1').query()).toBeNull();
+		await expect.element(page.getByTestId('annotation-delete-ann-1')).not.toBeInTheDocument();
 	});
 });

frontend/src/lib/document/annotation/AnnotationShape.svelte.spec.ts

@@ -45,7 +45,7 @@ describe('AnnotationShape', () => {
 			onpointerleave: () => {}
 		});
 
-		expect(page.getByTestId('annotation-delete-ann-1').query()).toBeNull();
+		await expect.element(page.getByTestId('annotation-delete-ann-1')).not.toBeInTheDocument();
 	});
 
 	it('does not show delete button when showDelete is true but neither hovered nor active', async () => {
@@ -60,7 +60,7 @@ describe('AnnotationShape', () => {
 			onpointerleave: () => {}
 		});
 
-		expect(page.getByTestId('annotation-delete-ann-1').query()).toBeNull();
+		await expect.element(page.getByTestId('annotation-delete-ann-1')).not.toBeInTheDocument();
 	});
 
 	it('shows delete button when showDelete is true and isHovered is true', async () => {

frontend/src/lib/document/transcription/TranscriptionEditView.svelte.test.ts

@@ -5,9 +5,6 @@ import { page } from 'vitest/browser';
 vi.mock('$lib/shared/services/confirm.svelte', () => ({
 	getConfirmService: () => ({ confirm: async () => false })
 }));
-vi.mock('$lib/shared/services/confirm.svelte.js', () => ({
-	getConfirmService: () => ({ confirm: async () => false })
-}));
 
 const { default: TranscriptionEditView } = await import('./TranscriptionEditView.svelte');
 import type { TranscriptionBlockData } from '$lib/shared/types';

frontend/src/lib/document/viewer/PdfViewer.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
-import { onMount, setContext } from 'svelte';
-import { createPdfRenderer } from '$lib/document/viewer/usePdfRenderer.svelte';
+import { onMount, setContext, untrack } from 'svelte';
+import { createPdfRenderer, type LibLoader } from '$lib/document/viewer/usePdfRenderer.svelte';
 import PdfControls from './PdfControls.svelte';
 import AnnotationLayer from '$lib/document/annotation/AnnotationLayer.svelte';
 import type { Annotation } from '$lib/shared/types';
@@ -21,7 +21,8 @@ let {
 	onDeleteAnnotationRequest,
 	documentFileHash,
 	annotationsDimmed = false,
-	flashAnnotationId = null
+	flashAnnotationId = null,
+	libLoader = undefined
 }: {
 	url: string;
 	documentId?: string;
@@ -35,9 +36,11 @@ let {
 	documentFileHash?: string | null;
 	annotationsDimmed?: boolean;
 	flashAnnotationId?: string | null;
+	libLoader?: LibLoader;
 } = $props();
 
-const renderer = createPdfRenderer();
+// untrack: libLoader prop change must not reinitialise the renderer
+const renderer = untrack(() => createPdfRenderer(libLoader));
 
 // Canvas and text layer container refs — bound via bind:this
 let canvasEl = $state<HTMLCanvasElement | null>(null);

frontend/src/lib/document/viewer/PdfViewer.svelte.spec.ts

@@ -1,53 +0,0 @@
-import { vi, describe, it, expect, afterEach } from 'vitest';
-import { cleanup, render } from 'vitest-browser-svelte';
-import { page } from 'vitest/browser';
-
-// pdfjs-dist is a rendering dependency — we mock it so unit tests don't need
-// a real browser PDF engine. The interesting behaviour under test here is the
-// component's own UI logic (controls, page counter), not pdfjs internals.
-vi.mock('pdfjs-dist', () => {
-	function TextLayerMock() {}
-	TextLayerMock.prototype.render = () => Promise.resolve();
-	TextLayerMock.prototype.cancel = () => {};
-
-	return {
-		GlobalWorkerOptions: { workerSrc: '' },
-		getDocument: vi.fn().mockReturnValue({
-			promise: Promise.resolve({
-				numPages: 2,
-				getPage: vi.fn().mockResolvedValue({
-					getViewport: vi.fn().mockReturnValue({ width: 595, height: 842 }),
-					render: vi.fn().mockReturnValue({ promise: Promise.resolve() }),
-					streamTextContent: vi.fn().mockReturnValue(new ReadableStream())
-				})
-			})
-		}),
-		TextLayer: TextLayerMock
-	};
-});
-
-vi.mock('pdfjs-dist/build/pdf.worker.min.mjs?url', () => ({ default: '' }));
-
-import PdfViewer from './PdfViewer.svelte';
-
-afterEach(cleanup);
-
-describe('PdfViewer', () => {
-	it('shows previous and next page navigation buttons', async () => {
-		render(PdfViewer, { url: '/api/documents/test-id/file' });
-		await expect.element(page.getByRole('button', { name: /zurück/i })).toBeInTheDocument();
-		await expect.element(page.getByRole('button', { name: /weiter/i })).toBeInTheDocument();
-	});
-
-	it('shows zoom controls', async () => {
-		render(PdfViewer, { url: '/api/documents/test-id/file' });
-		await expect.element(page.getByRole('button', { name: /vergrößern/i })).toBeInTheDocument();
-		await expect.element(page.getByRole('button', { name: /verkleinern/i })).toBeInTheDocument();
-	});
-
-	it('displays the page counter once the PDF has loaded', async () => {
-		render(PdfViewer, { url: '/api/documents/test-id/file' });
-		// Mock resolves synchronously, so "1 / 2" should appear quickly
-		await expect.element(page.getByText(/1\s*\/\s*2/)).toBeInTheDocument();
-	});
-});

frontend/src/lib/document/viewer/PdfViewer.svelte.test.ts

@@ -1,43 +1,20 @@
 import { describe, it, expect, vi, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page } from 'vitest/browser';
-
-vi.mock('pdfjs-dist', () => {
-	function TextLayerMock() {}
-	TextLayerMock.prototype.render = () => Promise.resolve();
-	TextLayerMock.prototype.cancel = () => {};
-
-	return {
-		GlobalWorkerOptions: { workerSrc: '' },
-		getDocument: vi.fn().mockReturnValue({
-			promise: Promise.resolve({
-				numPages: 2,
-				getPage: vi.fn().mockResolvedValue({
-					getViewport: vi.fn().mockReturnValue({ width: 595, height: 842 }),
-					render: vi.fn().mockReturnValue({ promise: Promise.resolve() }),
-					streamTextContent: vi.fn().mockReturnValue(new ReadableStream())
-				})
-			})
-		}),
-		TextLayer: TextLayerMock
-	};
-});
-
-vi.mock('pdfjs-dist/build/pdf.worker.min.mjs?url', () => ({ default: '' }));
-
-const { default: PdfViewer } = await import('./PdfViewer.svelte');
+import PdfViewer from './PdfViewer.svelte';
+import { makeFakeLibLoader } from './testHelpers';
 
 afterEach(cleanup);
 
 describe('PdfViewer — empty / error states', () => {
 	it('renders the no-file placeholder when url is empty', async () => {
-		render(PdfViewer, { url: '' });
+		render(PdfViewer, { url: '', libLoader: makeFakeLibLoader() });
 
 		await expect.element(page.getByText('Keine Datei vorhanden')).toBeVisible();
 	});
 
 	it('does not render the controls when url is empty', async () => {
-		render(PdfViewer, { url: '' });
+		render(PdfViewer, { url: '', libLoader: makeFakeLibLoader() });
 
 		const buttons = document.querySelectorAll('button');
 		expect(buttons.length).toBe(0);
@@ -49,10 +26,10 @@ describe('PdfViewer — loaded state', () => {
 		render(PdfViewer, {
 			url: '/api/documents/test/file',
 			documentId: 'test',
-			annotationReloadKey: 0
+			annotationReloadKey: 0,
+			libLoader: makeFakeLibLoader()
 		});
 
-		// PdfControls renders its nav + zoom buttons once the document.promise resolves.
 		await expect.element(page.getByRole('button', { name: 'Zurück' })).toBeVisible();
 		await expect.element(page.getByRole('button', { name: 'Weiter' })).toBeVisible();
 		await expect.element(page.getByRole('button', { name: 'Vergrößern' })).toBeVisible();
@@ -63,7 +40,8 @@ describe('PdfViewer — loaded state', () => {
 		render(PdfViewer, {
 			url: '/api/documents/test/file',
 			documentId: 'test',
-			annotationsDimmed: true
+			annotationsDimmed: true,
+			libLoader: makeFakeLibLoader()
 		});
 
 		await vi.waitFor(() => {
@@ -96,11 +74,10 @@ describe('PdfViewer — loaded state', () => {
 				url: '/api/documents/test/file',
 				documentId: 'test',
 				transcribeMode: true,
-				documentFileHash: 'match'
+				documentFileHash: 'match',
+				libLoader: makeFakeLibLoader()
 			});
 
-			// transcribeMode forces showAnnotations=true; toggle button surfaces with "hide" label
-			// (only when annotationCount > 0).
 			await expect
 				.element(page.getByRole('button', { name: /annotierungen verbergen/i }))
 				.toBeVisible();
@@ -113,7 +90,8 @@ describe('PdfViewer — loaded state', () => {
 		render(PdfViewer, {
 			url: '/api/documents/test/file',
 			documentId: 'test',
-			documentFileHash: 'abc123'
+			documentFileHash: 'abc123',
+			libLoader: makeFakeLibLoader()
 		});
 
 		await vi.waitFor(() => {
@@ -125,7 +103,8 @@ describe('PdfViewer — loaded state', () => {
 		render(PdfViewer, {
 			url: '/api/documents/test/file',
 			documentId: 'test',
-			flashAnnotationId: 'ann-flashing'
+			flashAnnotationId: 'ann-flashing',
+			libLoader: makeFakeLibLoader()
 		});
 
 		await expect.element(page.getByRole('button', { name: 'Zurück' })).toBeVisible();
@@ -135,7 +114,8 @@ describe('PdfViewer — loaded state', () => {
 		render(PdfViewer, {
 			url: '/api/documents/test/file',
 			documentId: 'test',
-			blockNumbers: { 'ann-1': 1, 'ann-2': 2 }
+			blockNumbers: { 'ann-1': 1, 'ann-2': 2 },
+			libLoader: makeFakeLibLoader()
 		});
 
 		await expect.element(page.getByRole('button', { name: 'Zurück' })).toBeVisible();
@@ -145,7 +125,8 @@ describe('PdfViewer — loaded state', () => {
 		render(PdfViewer, {
 			url: '/api/documents/test/file',
 			documentId: 'test',
-			activeAnnotationId: 'ann-1'
+			activeAnnotationId: 'ann-1',
+			libLoader: makeFakeLibLoader()
 		});
 
 		await expect.element(page.getByRole('button', { name: 'Zurück' })).toBeVisible();
@@ -156,10 +137,10 @@ describe('PdfViewer — loaded state', () => {
 			url: '/api/documents/test/file',
 			documentId: 'test',
 			transcribeMode: true,
-			activeAnnotationId: 'ann-1'
+			activeAnnotationId: 'ann-1',
+			libLoader: makeFakeLibLoader()
 		});
 
-		// Without an annotations fetch, the visibility toggle is hidden — just assert the always-on nav.
 		await expect.element(page.getByRole('button', { name: 'Zurück' })).toBeVisible();
 		await expect.element(page.getByRole('button', { name: 'Weiter' })).toBeVisible();
 	});
@@ -169,7 +150,8 @@ describe('PdfViewer — loaded state', () => {
 		render(PdfViewer, {
 			url: '/api/documents/test/file',
 			documentId: 'test',
-			onAnnotationClick
+			onAnnotationClick,
+			libLoader: makeFakeLibLoader()
 		});
 
 		await expect.element(page.getByRole('button', { name: 'Zurück' })).toBeVisible();
@@ -199,7 +181,8 @@ describe('PdfViewer — loaded state', () => {
 			render(PdfViewer, {
 				url: '/api/documents/test/file',
 				documentId: 'test',
-				documentFileHash: 'new-hash'
+				documentFileHash: 'new-hash',
+				libLoader: makeFakeLibLoader()
 			});
 
 			await vi.waitFor(() => {
@@ -234,10 +217,10 @@ describe('PdfViewer — loaded state', () => {
 			render(PdfViewer, {
 				url: '/api/documents/test/file',
 				documentId: 'test',
-				documentFileHash: 'matching-hash'
+				documentFileHash: 'matching-hash',
+				libLoader: makeFakeLibLoader()
 			});
 
-			// Controls finish mounting, and the outdated notice stays absent.
 			await expect.element(page.getByRole('button', { name: 'Zurück' })).toBeVisible();
 			expect(document.querySelector('[data-testid="annotation-outdated-notice"]')).toBeNull();
 		} finally {
@@ -250,10 +233,10 @@ describe('PdfViewer — loaded state', () => {
 		try {
 			render(PdfViewer, {
 				url: '/api/documents/test/file',
-				documentId: 'test'
+				documentId: 'test',
+				libLoader: makeFakeLibLoader()
 			});
 
-			// PDF rendering does not depend on the annotations fetch — controls still appear.
 			await expect.element(page.getByRole('button', { name: 'Zurück' })).toBeVisible();
 			expect(document.querySelector('[data-testid="annotation-outdated-notice"]')).toBeNull();
 		} finally {
@@ -268,7 +251,8 @@ describe('PdfViewer — loaded state', () => {
 		try {
 			render(PdfViewer, {
 				url: '/api/documents/test/file',
-				documentId: 'test'
+				documentId: 'test',
+				libLoader: makeFakeLibLoader()
 			});
 
 			await expect.element(page.getByRole('button', { name: 'Zurück' })).toBeVisible();
@@ -277,4 +261,21 @@ describe('PdfViewer — loaded state', () => {
 			fetchSpy.mockRestore();
 		}
 	});
+
+	it('shows previous and next page navigation buttons', async () => {
+		render(PdfViewer, { url: '/api/documents/test-id/file', libLoader: makeFakeLibLoader() });
+		await expect.element(page.getByRole('button', { name: /zurück/i })).toBeVisible();
+		await expect.element(page.getByRole('button', { name: /weiter/i })).toBeVisible();
+	});
+
+	it('shows zoom controls', async () => {
+		render(PdfViewer, { url: '/api/documents/test-id/file', libLoader: makeFakeLibLoader() });
+		await expect.element(page.getByRole('button', { name: /vergrößern/i })).toBeVisible();
+		await expect.element(page.getByRole('button', { name: /verkleinern/i })).toBeVisible();
+	});
+
+	it('displays the page counter once the PDF has loaded', async () => {
+		render(PdfViewer, { url: '/api/documents/test-id/file', libLoader: makeFakeLibLoader() });
+		await expect.element(page.getByText(/1\s*\/\s*2/)).toBeVisible();
+	});
 });

frontend/src/lib/document/viewer/testHelpers.ts

@@ -0,0 +1,31 @@
+import { vi } from 'vitest';
+import type { LibLoader } from './usePdfRenderer.svelte';
+
+export function makeFakePdfjsLib() {
+	class TextLayerMock {
+		render() {
+			return Promise.resolve();
+		}
+		cancel() {}
+	}
+
+	return {
+		GlobalWorkerOptions: { workerSrc: '' },
+		getDocument: vi.fn().mockReturnValue({
+			promise: Promise.resolve({
+				numPages: 2,
+				getPage: vi.fn().mockResolvedValue({
+					getViewport: vi.fn().mockReturnValue({ width: 595, height: 842 }),
+					render: vi.fn().mockReturnValue({ promise: Promise.resolve() }),
+					streamTextContent: vi.fn().mockReturnValue(new ReadableStream())
+				})
+			})
+		}),
+		TextLayer: TextLayerMock
+	} as unknown as typeof import('pdfjs-dist');
+}
+
+export function makeFakeLibLoader(): LibLoader {
+	const fakePdfjs = makeFakePdfjsLib();
+	return vi.fn().mockResolvedValue([fakePdfjs, { default: '' }] as const);
+}

frontend/src/lib/document/viewer/usePdfRenderer.svelte.test.ts

@@ -1,5 +1,6 @@
-import { describe, it, expect } from 'vitest';
+import { describe, it, expect, vi } from 'vitest';
 import { createPdfRenderer } from './usePdfRenderer.svelte';
+import { makeFakeLibLoader } from './testHelpers';
 
 // Note: init() and loadDocument() require pdfjsLib (browser module).
 // These tests cover pure state logic only — bounds clamping and zoom limits.
@@ -122,39 +123,36 @@ describe('createPdfRenderer', () => {
 		expect(r.scale).toBe(before);
 	});
 
-	it('init() is callable and resolves without throwing in browser env', async () => {
-		const r = createPdfRenderer();
+	it('init() sets pdfjsReady to true when loader resolves', async () => {
+		const r = createPdfRenderer(makeFakeLibLoader());
 		await expect(r.init()).resolves.toBeUndefined();
-		// pdfjsReady is now true
 		expect(r.pdfjsReady).toBe(true);
 	});
 
-	it('after init, loadDocument with a bogus URL sets error', async () => {
-		const r = createPdfRenderer();
+	it('after init, loadDocument completes and loading returns to false', async () => {
+		const r = createPdfRenderer(makeFakeLibLoader());
 		await r.init();
 
-		await r.loadDocument('about:invalid-pdf');
-		// Either error is set or loading flips back to false — both are acceptable
+		await r.loadDocument('/some/path');
 		expect(r.loading).toBe(false);
 	});
 
 	it('renderCurrentPage is a no-op when canvasEl is null but pdfjsLib is initialized', async () => {
-		const r = createPdfRenderer();
+		const r = createPdfRenderer(makeFakeLibLoader());
 		await r.init();
 		// Without setElements, canvasEl is null — early return
 		await expect(r.renderCurrentPage()).resolves.toBeUndefined();
 	});
 
 	it('renderCurrentPage is a no-op when textLayerEl is null', async () => {
-		const r = createPdfRenderer();
+		const r = createPdfRenderer(makeFakeLibLoader());
 		await r.init();
-		// Set only canvas, leave textLayer unset is not directly testable;
-		// confirm calling without elements wired returns early.
+		// Without setElements, textLayerEl is null — early return
 		await expect(r.renderCurrentPage()).resolves.toBeUndefined();
 	});
 
 	it('init() can be called multiple times safely', async () => {
-		const r = createPdfRenderer();
+		const r = createPdfRenderer(makeFakeLibLoader());
 		await r.init();
 		await r.init();
 		expect(r.pdfjsReady).toBe(true);
@@ -173,4 +171,57 @@ describe('createPdfRenderer', () => {
 		r.goToPage(1);
 		expect(r.currentPage).toBe(1);
 	});
+
+	it('calls injected libLoader during init and sets pdfjsReady', async () => {
+		const fakePdfjs = {
+			GlobalWorkerOptions: { workerSrc: '' },
+			getDocument: vi.fn(),
+			TextLayer: class {}
+		} as unknown as typeof import('pdfjs-dist');
+		const fakeLoader = vi.fn().mockResolvedValue([fakePdfjs, { default: '' }] as const);
+		const r = createPdfRenderer(fakeLoader);
+		await r.init();
+		expect(fakeLoader).toHaveBeenCalledOnce();
+		expect(r.pdfjsReady).toBe(true);
+	});
+
+	it('leaves pdfjsReady false when libLoader rejects', async () => {
+		const failingLoader = vi.fn().mockRejectedValue(new Error('load failed'));
+		const r = createPdfRenderer(failingLoader);
+		await expect(r.init()).rejects.toThrow('load failed');
+		expect(r.pdfjsReady).toBe(false);
+	});
+
+	it('init() is idempotent — libLoader called only once on repeated calls', async () => {
+		const fakePdfjs = {
+			GlobalWorkerOptions: { workerSrc: '' },
+			getDocument: vi.fn(),
+			TextLayer: class {}
+		} as unknown as typeof import('pdfjs-dist');
+		const fakeLoader = vi.fn().mockResolvedValue([fakePdfjs, { default: '' }] as const);
+		const r = createPdfRenderer(fakeLoader);
+		await r.init();
+		await r.init();
+		expect(fakeLoader).toHaveBeenCalledOnce();
+	});
+
+	it('loadDocument sets error and loading=false when getDocument().promise rejects', async () => {
+		const failingLib = {
+			GlobalWorkerOptions: { workerSrc: '' },
+			getDocument: vi.fn().mockReturnValue({
+				promise: Promise.reject(new Error('PDF not found'))
+			}),
+			TextLayer: class {
+				render() {
+					return Promise.resolve();
+				}
+				cancel() {}
+			}
+		} as unknown as typeof import('pdfjs-dist');
+		const r = createPdfRenderer(vi.fn().mockResolvedValue([failingLib, { default: '' }] as const));
+		await r.init();
+		await r.loadDocument('/bad/path');
+		expect(r.loading).toBe(false);
+		expect(r.error).toBe('PDF not found');
+	});
 });

frontend/src/lib/document/viewer/usePdfRenderer.svelte.ts

@@ -1,6 +1,11 @@
 import type { PDFDocumentProxy, RenderTask } from 'pdfjs-dist';
 
-export function createPdfRenderer() {
+export type LibLoader = () => Promise<readonly [typeof import('pdfjs-dist'), { default: string }]>;
+
+const defaultLibLoader: LibLoader = () =>
+	Promise.all([import('pdfjs-dist'), import('pdfjs-dist/build/pdf.worker.min.mjs?url')]);
+
+export function createPdfRenderer(libLoader: LibLoader = defaultLibLoader) {
 	// Reactive state — exposed via getters
 	let currentPage = $state(1);
 	let totalPages = $state(0);
@@ -18,10 +23,8 @@ export function createPdfRenderer() {
 	let pdfjsLib: typeof import('pdfjs-dist') | null = null;
 
 	async function init(): Promise<void> {
-		const [lib, { default: workerUrl }] = await Promise.all([
-			import('pdfjs-dist'),
-			import('pdfjs-dist/build/pdf.worker.min.mjs?url')
-		]);
+		if (pdfjsReady) return;
+		const [lib, { default: workerUrl }] = await libLoader();
 		lib.GlobalWorkerOptions.workerSrc = workerUrl;
 		pdfjsLib = lib;
 		pdfjsReady = true;

frontend/src/lib/notification/NotificationDropdown.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+import { goto } from '$app/navigation';
 import { m } from '$lib/paraglide/messages.js';
 import { relativeTime } from '$lib/shared/utils/time';
 import type { NotificationItem } from '$lib/notification/notifications.svelte';
@@ -11,6 +12,11 @@ type Props = {
 };
 
 let { notifications, onMarkRead, onMarkAllRead, onClose }: Props = $props();
+
+function handleViewAll() {
+	onClose(); // close first — avoids stale dropdown during navigation transition
+	goto('/aktivitaeten');
+}
 </script>
 
 <div
@@ -127,12 +133,12 @@ let { notifications, onMarkRead, onMarkAllRead, onClose }: Props = $props();
 	{/if}
 
 	<div class="border-t border-line px-4 py-2">
-		<a
-			href="/aktivitaeten"
-			onclick={onClose}
-			class="text-xs font-medium text-ink-2 transition-colors hover:text-ink"
+		<button
+			type="button"
+			onclick={handleViewAll}
+			class="min-h-[44px] px-1 text-xs font-medium text-ink-2 transition-colors hover:text-ink"
 		>
 			{m.chronik_view_all()}
-		</a>
+		</button>
 	</div>
 </div>

frontend/src/lib/notification/NotificationDropdown.svelte.test.ts

@@ -1,9 +1,15 @@
 import { describe, it, expect, vi, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page } from 'vitest/browser';
+import { goto } from '$app/navigation';
 import NotificationDropdown from './NotificationDropdown.svelte';
 
-afterEach(cleanup);
+vi.mock('$app/navigation', () => ({ goto: vi.fn() }));
+
+afterEach(() => {
+	cleanup();
+	vi.clearAllMocks();
+});
 
 const makeNotification = (overrides: Record<string, unknown> = {}) => ({
 	id: 'n1',
@@ -153,7 +159,7 @@ describe('NotificationDropdown', () => {
 		expect(onMarkAllRead).toHaveBeenCalledOnce();
 	});
 
-	it('calls onClose when the view-all link is clicked', async () => {
+	it('calls onClose when the view-all button is clicked', async () => {
 		const onClose = vi.fn();
 		render(NotificationDropdown, {
 			props: {
@@ -164,11 +170,44 @@ describe('NotificationDropdown', () => {
 			}
 		});
 
-		await page.getByRole('link').click();
+		await page.getByRole('button', { name: /alle aktivitäten|view all/i }).click();
 
 		expect(onClose).toHaveBeenCalledOnce();
 	});
 
+	it('navigates to /aktivitaeten when the view-all button is clicked', async () => {
+		render(NotificationDropdown, {
+			props: {
+				notifications: [],
+				onMarkRead: () => {},
+				onMarkAllRead: () => {},
+				onClose: () => {}
+			}
+		});
+
+		await page.getByRole('button', { name: /alle aktivitäten|view all/i }).click();
+
+		expect(goto).toHaveBeenCalledWith('/aktivitaeten');
+	});
+
+	it('calls onClose before navigating to /aktivitaeten', async () => {
+		const callOrder: string[] = [];
+		const onClose = vi.fn(() => callOrder.push('close'));
+		vi.mocked(goto).mockImplementation(() => callOrder.push('goto'));
+		render(NotificationDropdown, {
+			props: {
+				notifications: [],
+				onMarkRead: () => {},
+				onMarkAllRead: () => {},
+				onClose
+			}
+		});
+
+		await page.getByRole('button', { name: /alle aktivitäten|view all/i }).click();
+
+		expect(callOrder).toEqual(['close', 'goto']);
+	});
+
 	it('renders MENTION items with the mention verb text', async () => {
 		render(NotificationDropdown, {
 			props: {

frontend/src/lib/ocr/OcrTrainingCard.svelte.spec.ts

@@ -1,4 +1,4 @@
-import { afterEach, describe, expect, it, vi } from 'vitest';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page } from 'vitest/browser';
 import OcrTrainingCard from './OcrTrainingCard.svelte';
@@ -74,6 +74,12 @@ describe('OcrTrainingCard — enabled state', () => {
 });
 
 describe('OcrTrainingCard — success dismiss button', () => {
+	beforeEach(() => vi.useFakeTimers());
+	afterEach(() => {
+		vi.runAllTimers();
+		vi.useRealTimers();
+	});
+
 	it('dismiss button has 44×44px touch target (h-11 w-11)', async () => {
 		vi.stubGlobal('fetch', vi.fn().mockResolvedValue({ ok: true }));
 
@@ -108,7 +114,9 @@ describe('OcrTrainingCard — in-flight state', () => {
 		// While fetch is still pending the button label becomes "…"
 		await expect.element(page.getByRole('button', { name: '…' })).toBeInTheDocument();
 
-		// Cleanup: resolve the pending promise
 		resolveFetch({ ok: false });
+		await expect
+			.element(page.getByRole('button', { name: /Training starten/i }))
+			.not.toBeDisabled();
 	});
 });

frontend/src/routes/+layout.svelte

@@ -9,7 +9,7 @@ import NotificationBell from '$lib/notification/NotificationBell.svelte';
 import AppNav from './AppNav.svelte';
 import UserMenu from './UserMenu.svelte';
 import ConfirmDialog from '$lib/shared/primitives/ConfirmDialog.svelte';
-import { provideConfirmService } from '$lib/shared/services/confirm.svelte.js';
+import { provideConfirmService } from '$lib/shared/services/confirm.svelte';
 import { bulkSelectionStore } from '$lib/document/bulkSelection.svelte';
 
 let { children, data } = $props();

frontend/src/routes/admin/groups/[id]/page.svelte.test.ts

@@ -2,7 +2,7 @@ import { describe, it, expect, vi, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page } from 'vitest/browser';
 
-vi.mock('$lib/shared/services/confirm.svelte.js', () => ({
+vi.mock('$lib/shared/services/confirm.svelte', () => ({
 	getConfirmService: () => ({ confirm: async () => false })
 }));
 

frontend/src/routes/admin/tags/[id]/TagDeleteGuard.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
 import { enhance } from '$app/forms';
 import { m } from '$lib/paraglide/messages.js';
-import { getConfirmService } from '$lib/shared/services/confirm.svelte.js';
+import { getConfirmService } from '$lib/shared/services/confirm.svelte';
 
 type FlatTag = {
 	id: string;

frontend/src/routes/admin/tags/[id]/page.svelte.test.ts

@@ -16,9 +16,6 @@ vi.mock('$app/stores', () => ({
 vi.mock('$lib/shared/services/confirm.svelte', () => ({
 	getConfirmService: () => ({ confirm: async () => false })
 }));
-vi.mock('$lib/shared/services/confirm.svelte.js', () => ({
-	getConfirmService: () => ({ confirm: async () => false })
-}));
 
 vi.mock('$app/navigation', () => ({
 	beforeNavigate: () => {},

frontend/src/routes/admin/users/[id]/page.svelte.test.ts

@@ -5,9 +5,6 @@ import { page } from 'vitest/browser';
 vi.mock('$lib/shared/services/confirm.svelte', () => ({
 	getConfirmService: () => ({ confirm: async () => false })
 }));
-vi.mock('$lib/shared/services/confirm.svelte.js', () => ({
-	getConfirmService: () => ({ confirm: async () => false })
-}));
 
 const { default: AdminUserEditPage } = await import('./+page.svelte');
 

frontend/src/routes/documents/[id]/+page.svelte

@@ -12,7 +12,7 @@ import { createOcrJob } from '$lib/ocr/useOcrJob.svelte';
 import { createTranscriptionBlocks } from '$lib/document/transcription/useTranscriptionBlocks.svelte';
 import { createFileLoader } from '$lib/document/viewer/useFileLoader.svelte';
 import { scrollToCommentFromQuery } from '$lib/shared/utils/deepLinkScroll';
-import { getConfirmService } from '$lib/shared/services/confirm.svelte.js';
+import { getConfirmService } from '$lib/shared/services/confirm.svelte';
 
 let { data } = $props();
 

frontend/src/routes/documents/[id]/edit/page.svelte.test.ts

@@ -1,7 +1,7 @@
 import { describe, it, expect, vi, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 
-vi.mock('$lib/shared/services/confirm.svelte.js', () => ({
+vi.mock('$lib/shared/services/confirm.svelte', () => ({
 	getConfirmService: () => ({ confirm: async () => false })
 }));
 

frontend/src/routes/documents/[id]/page.svelte.test.ts

@@ -30,9 +30,6 @@ vi.mock('$app/navigation', () => ({
 vi.mock('$lib/shared/services/confirm.svelte', () => ({
 	getConfirmService: () => ({ confirm: async () => false })
 }));
-vi.mock('$lib/shared/services/confirm.svelte.js', () => ({
-	getConfirmService: () => ({ confirm: async () => false })
-}));
 
 const { default: DocumentDetailPage } = await import('./+page.svelte');
 

frontend/src/routes/hilfe/transkription/+page.svelte

@@ -125,15 +125,3 @@ const klaerungChips = [
 		<p class="font-serif text-sm leading-relaxed text-ink-2">{m.richtlinien_closing_body()}</p>
 	</div>
 </main>
-
-<style>
-@media print {
-	:global(.app-nav) {
-		display: none;
-	}
-
-	@page {
-		margin: 1.5cm;
-	}
-}
-</style>

frontend/src/routes/layout.css

@@ -459,3 +459,34 @@
 		transform: translateX(350%);
 	}
 }
+
+@media print {
+	:global(.app-nav) {
+		display: none;
+	}
+
+	@page {
+		margin: 1.5cm;
+	}
+}
+
+.chronik-fade-in {
+	animation: chronik-fade-in 160ms ease-out;
+}
+
+@keyframes chronik-fade-in {
+	from {
+		opacity: 0;
+		transform: translateY(-4px);
+	}
+	to {
+		opacity: 1;
+		transform: translateY(0);
+	}
+}
+
+@media (prefers-reduced-motion: reduce) {
+	.chronik-fade-in {
+		animation: none;
+	}
+}

frontend/src/routes/persons/[id]/edit/NameHistoryEditCard.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
 import { enhance } from '$app/forms';
 import { m } from '$lib/paraglide/messages.js';
-import { getConfirmService } from '$lib/shared/services/confirm.svelte.js';
+import { getConfirmService } from '$lib/shared/services/confirm.svelte';
 
 interface Props {
 	aliases: Array<{

frontend/src/routes/persons/[id]/edit/page.svelte.test.ts

@@ -5,9 +5,6 @@ import { page } from 'vitest/browser';
 vi.mock('$lib/shared/services/confirm.svelte', () => ({
 	getConfirmService: () => ({ confirm: async () => false })
 }));
-vi.mock('$lib/shared/services/confirm.svelte.js', () => ({
-	getConfirmService: () => ({ confirm: async () => false })
-}));
 
 const { default: PersonEditPage } = await import('./+page.svelte');
 

frontend/src/test-setup.ts

@@ -0,0 +1,14 @@
+// Disable SvelteKit hover-prefetch (both data + code) in browser-mode tests.
+// ADR-012 / #553.
+//
+// Hover-prefetch fires real fetch requests for route loader chunks; those
+// requests go through the same Playwright route handler that serves mocked
+// modules. An in-flight prefetch landing after iframe teardown can hit the
+// route handler with a closed birpc channel, raising an unhandled rejection
+// that exits the run with code 1 even when every individual test was green.
+//
+// `data-sveltekit-preload-data="off"` disables loader-data prefetch;
+// `data-sveltekit-preload-code="off"` disables route-code chunk prefetch.
+// Both surfaces can produce late module fetches that hit the route handler.
+document.body.dataset.sveltekitPreloadData = 'off';
+document.body.dataset.sveltekitPreloadCode = 'off';

frontend/vite.config.ts

@@ -77,6 +77,7 @@ export default defineConfig({
 						screenshotDirectory: 'test-results/screenshots',
 						screenshotFailures: true
 					},
+					setupFiles: ['./src/test-setup.ts'],
 					include: ['src/**/*.svelte.{test,spec}.{js,ts}'],
 					exclude: ['src/lib/server/**']
 				}

frontend/vitest.client-coverage.config.ts

@@ -32,6 +32,7 @@ export default defineConfig({
 			screenshotDirectory: 'test-results/screenshots',
 			screenshotFailures: true
 		},
+		setupFiles: ['./src/test-setup.ts'],
 		include: ['src/**/*.svelte.{test,spec}.{js,ts}'],
 		exclude: ['src/lib/server/**'],
 		coverage: {
@@ -43,7 +44,8 @@ export default defineConfig({
 			thresholds: {
 				lines: 80,
 				functions: 80,
-				branches: 80,
+				// branches at 75 — long-tail parent/child accounting grind; see docs/adr/013-client-branches-coverage-threshold.md and #496
+				branches: 75,
 				statements: 80
 			}
 		}