refactor(stammbaum): TestNode type alias drops generation cast (#361)

Introduces a local `type TestNode = { id: string; generation: number | null }`
so the three AC3 test fixtures can write `generation: null` directly,
without the awkward `as number | null` cast next to the literal `generation:
2`. Sara cycle-3 cosmetic; same predicate, cleaner reading.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docs/adr/026-stammbaum-layout-in-house.md

@@ -107,6 +107,16 @@ threshold, so `packBlocks.ts` is **not** yet warranted.
           AND parent.generation IS NOT NULL
     );
   ```
+
+  The same predicate is encoded as a unit-testable JavaScript function — see
+  `findAc3Candidates()` in
+  `frontend/src/lib/person/genealogy/__fixtures__/findAc3Candidates.mjs`,
+  asserted against the committed canonical fixture by
+  `validateFixture.test.ts`, and emitted as a stderr soft-warn by
+  `frontend/scripts/capture-network-fixture.mjs` on every recapture. The SQL
+  is the source-of-truth probe against live data; the function is the
+  capture-time and fixture-time signal that the predicate's count crossed
+  zero.
 - **AC6 — Bundle-impact gate (≤ 40 kB gzipped on `/stammbaum`).** Moot under
   this ADR; reactivates only under ADR-027 (dagre adoption).
 - **AC7 — Visual regression at 320 / 768 / 1440.** `toHaveScreenshot()`

frontend/scripts/capture-network-fixture.mjs

@@ -11,6 +11,8 @@ import { dirname } from 'node:path';
 import { fileURLToPath } from 'node:url';
 import { randomUUID } from 'node:crypto';
 
+import { findAc3Candidates } from '../src/lib/person/genealogy/__fixtures__/findAc3Candidates.mjs';
+
 const BACKEND_URL = process.env.BACKEND_URL ?? 'http://localhost:8080';
 const EMAIL = process.env.CAPTURE_EMAIL;
 const PASSWORD = process.env.CAPTURE_PASSWORD;
@@ -59,9 +61,10 @@ const FIXTURE_PATH = `${HERE}/../src/lib/person/genealogy/__fixtures__/stammbaum
 // nodes, 5 generations, 28 SPOUSE_OF edges, 1 multi-spouse person). The point
 // is catching a silently empty backend or a structurally-regressed snapshot,
 // not strict size validation; raise these only if the canonical graph grows
-// substantially. The same gates are unit-tested at
-// src/lib/person/genealogy/__fixtures__/validateFixture.ts — keep both
-// definitions in sync.
+// substantially. The matching gates in
+// src/lib/person/genealogy/__fixtures__/validateFixture.ts cover unit-test
+// coverage; the floors are intentionally duplicated as numeric constants
+// (the AC3 revisit predicate, by contrast, now lives in one shared module).
 const MIN_NODES = 50;
 const MIN_GENERATIONS = 5;
 const MIN_SPOUSE_OF_EDGES = 1;
@@ -161,47 +164,6 @@ function countMultiSpousePersons(spouseEdges) {
 	return count;
 }
 
-// AC3 revisit-trigger predicate (ADR-026 §Notes). Returns the IDs of every
-// captured person matching "unseeded loose spouse whose parents are in graph".
-// A non-empty result is the documented revisit trigger for the dagre
-// deferral decision — emitted as a soft-warn (does not fail capture) so a
-// human-in-the-loop notices when the AC3 layout branch becomes reachable.
-// Mirrors the implementation in src/lib/person/genealogy/__fixtures__/
-// validateFixture.ts findAc3Candidates(); keep both in sync.
-function findAc3Candidates(network) {
-	const nodes = Array.isArray(network.nodes) ? network.nodes : [];
-	const edges = Array.isArray(network.edges) ? network.edges : [];
-	const generationById = new Map();
-	for (const n of nodes) {
-		if (n.id) generationById.set(n.id, n.generation);
-	}
-
-	const hasSpouseEdge = new Set();
-	const seededParentByChild = new Map();
-	for (const e of edges) {
-		if (!e.personId || !e.relatedPersonId) continue;
-		if (e.relationType === 'SPOUSE_OF') {
-			hasSpouseEdge.add(e.personId);
-			hasSpouseEdge.add(e.relatedPersonId);
-			continue;
-		}
-		if (e.relationType === 'PARENT_OF') {
-			const parentGen = generationById.get(e.personId);
-			if (parentGen != null) seededParentByChild.set(e.relatedPersonId, true);
-		}
-	}
-
-	const matches = [];
-	for (const n of nodes) {
-		if (!n.id) continue;
-		if (n.generation != null) continue;
-		if (!seededParentByChild.get(n.id)) continue;
-		if (!hasSpouseEdge.has(n.id)) continue;
-		matches.push(n.id);
-	}
-	return matches;
-}
-
 function mapAddToSet(map, key, value) {
 	const s = map.get(key);
 	if (s) s.add(value);

frontend/src/lib/person/genealogy/__fixtures__/findAc3Candidates.mjs

@@ -0,0 +1,55 @@
+// AC3 = "unseeded loose spouse whose parents are in the graph" (ADR-026).
+// Returns the IDs of every captured person matching the predicate. A non-
+// empty result is the documented revisit trigger for the dagre deferral
+// decision: the canonical-fixture unit suite asserts an empty result against
+// the committed JSON, and `frontend/scripts/capture-network-fixture.mjs`
+// soft-warns to stderr (does NOT fail capture) so a human-in-the-loop notices
+// when the layout branch becomes reachable.
+//
+// Lives as a plain ESM .mjs module so both the Node-run capture script and
+// the TypeScript validator/test suite can import it without a build step —
+// single source of truth for the predicate.
+
+/**
+ * @typedef {{ relationType?: string, personId?: string, relatedPersonId?: string }} Edge
+ * @typedef {{ id?: string, generation?: number | null }} Node
+ * @typedef {{ nodes?: Node[], edges?: Edge[] }} NetworkShape
+ */
+
+/**
+ * @param {NetworkShape} network
+ * @returns {string[]}
+ */
+export function findAc3Candidates(network) {
+	const nodes = Array.isArray(network.nodes) ? network.nodes : [];
+	const edges = Array.isArray(network.edges) ? network.edges : [];
+	const generationById = new Map();
+	for (const n of nodes) {
+		if (n.id) generationById.set(n.id, n.generation);
+	}
+
+	const hasSpouseEdge = new Set();
+	const seededParentByChild = new Map();
+	for (const e of edges) {
+		if (!e.personId || !e.relatedPersonId) continue;
+		if (e.relationType === 'SPOUSE_OF') {
+			hasSpouseEdge.add(e.personId);
+			hasSpouseEdge.add(e.relatedPersonId);
+			continue;
+		}
+		if (e.relationType === 'PARENT_OF') {
+			const parentGen = generationById.get(e.personId);
+			if (parentGen != null) seededParentByChild.set(e.relatedPersonId, true);
+		}
+	}
+
+	const matches = [];
+	for (const n of nodes) {
+		if (!n.id) continue;
+		if (n.generation != null) continue;
+		if (!seededParentByChild.get(n.id)) continue;
+		if (!hasSpouseEdge.has(n.id)) continue;
+		matches.push(n.id);
+	}
+	return matches;
+}

frontend/src/lib/person/genealogy/__fixtures__/validateFixture.test.ts

@@ -7,6 +7,11 @@ import canonicalFixture from './stammbaum.json';
 // buildLayout.test.ts relies on. Adding or removing a gate without updating
 // these tests is the failure we want to catch.
 
+// Lets `generation: null` typecheck without an inline `as number | null`
+// cast — the AC3 predicate cares specifically about the unseeded-node
+// branch, so the test fixtures need to express it directly.
+type TestNode = { id: string; generation: number | null };
+
 function networkWithNodes(count: number) {
 	return {
 		nodes: Array.from({ length: count }, (_, i) => ({ id: `n${i}`, generation: i % 6 })),
@@ -87,9 +92,9 @@ describe('findAc3Candidates — AC3 revisit-trigger predicate (#361, Elicit cycl
 	});
 
 	it('flags_an_unseeded_person_whose_seeded_parent_is_in_graph_and_who_has_a_spouse', () => {
-		const nodes = [
+		const nodes: TestNode[] = [
 			{ id: 'parent', generation: 2 },
-			{ id: 'child', generation: null as number | null },
+			{ id: 'child', generation: null },
 			{ id: 'spouse', generation: 3 }
 		];
 		const edges = [parentEdge('parent', 'child'), spouseEdge('child', 'spouse')];
@@ -100,9 +105,9 @@ describe('findAc3Candidates — AC3 revisit-trigger predicate (#361, Elicit cycl
 		// Unseeded + seeded parent in graph, but no SPOUSE_OF — not AC3 (the
 		// layout branch that hurts is the *loose spouse* branch). The capture
 		// warn must not fire here.
-		const nodes = [
+		const nodes: TestNode[] = [
 			{ id: 'parent', generation: 2 },
-			{ id: 'child', generation: null as number | null }
+			{ id: 'child', generation: null }
 		];
 		const edges = [parentEdge('parent', 'child')];
 		expect(findAc3Candidates({ nodes, edges })).toEqual([]);
@@ -112,9 +117,9 @@ describe('findAc3Candidates — AC3 revisit-trigger predicate (#361, Elicit cycl
 		// "Parents in graph" in the AC3 sense means at least one *seeded*
 		// parent. If both parent and child are unseeded the heuristic
 		// fallback already handles the case without AC3 ever firing.
-		const nodes = [
-			{ id: 'parent', generation: null as number | null },
-			{ id: 'child', generation: null as number | null },
+		const nodes: TestNode[] = [
+			{ id: 'parent', generation: null },
+			{ id: 'child', generation: null },
 			{ id: 'spouse', generation: 3 }
 		];
 		const edges = [parentEdge('parent', 'child'), spouseEdge('child', 'spouse')];

frontend/src/lib/person/genealogy/__fixtures__/validateFixture.ts

@@ -17,45 +17,11 @@ type Edge = { relationType?: string; personId?: string; relatedPersonId?: string
 type Node = { id?: string; generation?: number | null };
 export type NetworkShape = { nodes?: Node[]; edges?: Edge[] };
 
-// AC3 = "unseeded loose spouse whose parents are in the graph" (ADR-026).
-// Returns the IDs of every captured person matching the predicate. A non-
-// empty result is the documented revisit trigger for the dagre deferral
-// decision — the capture script logs a soft-warn (does NOT fail) on every
-// recapture so a human-in-the-loop notices when the layout branch becomes
-// reachable.
-export function findAc3Candidates(network: NetworkShape): string[] {
-	const nodes = Array.isArray(network.nodes) ? network.nodes : [];
-	const edges = Array.isArray(network.edges) ? network.edges : [];
-	const generationById = new Map<string, number | null | undefined>();
-	for (const n of nodes) {
-		if (n.id) generationById.set(n.id, n.generation);
-	}
-
-	const hasSpouseEdge = new Set<string>();
-	const seededParentByChild = new Map<string, boolean>();
-	for (const e of edges) {
-		if (!e.personId || !e.relatedPersonId) continue;
-		if (e.relationType === 'SPOUSE_OF') {
-			hasSpouseEdge.add(e.personId);
-			hasSpouseEdge.add(e.relatedPersonId);
-			continue;
-		}
-		if (e.relationType === 'PARENT_OF') {
-			const parentGen = generationById.get(e.personId);
-			if (parentGen != null) seededParentByChild.set(e.relatedPersonId, true);
-		}
-	}
-
-	const matches: string[] = [];
-	for (const n of nodes) {
-		if (!n.id) continue;
-		if (n.generation != null) continue;
-		if (!seededParentByChild.get(n.id)) continue;
-		if (!hasSpouseEdge.has(n.id)) continue;
-		matches.push(n.id);
-	}
-	return matches;
-}
+// The AC3 revisit-trigger predicate lives in a plain .mjs module so the
+// Node-run capture script and this TypeScript validator share one
+// implementation. Re-exported here so consumers of the fixture-directory
+// barrel keep their existing import surface.
+export { findAc3Candidates } from './findAc3Candidates.mjs';
 
 export type FixtureStats = {
 	nodes: number;