fix(bulk-edit): cycle-2 blockers — restore initial-* props, missing import, scope Esc, edit-mode topbar

Felix B1 (data-loss regression on /documents/[id]/edit) — DocumentEditLayout
still passes initialDateIso, initialLocation, initialDocumentLocation, but
my cycle-1 cleanup removed those props. Result: existing values rendered
empty and a save would have overwritten them with "". Restored the props
on WhoWhenSection and DescriptionSection; initialisation now lives in
onMount so it runs exactly once and never stomps a parent-driven update on
a later prop change.

Felix B2 — `DescriptionSection.svelte:36` still had the top-level
`currentTitle = untrack(() => initialTitle)` mutation that I cleaned up in
WhoWhenSection but missed here. Same onMount-once treatment.

Leonie B5 — `enrich/+page.svelte:105` referenced `<BulkSelectionBar>` but
the import was lost in a prettier pass; svelte-check errored out and the
bar never rendered, leaving an 8 rem dead zone from the pb-32 reservation.
One-line fix: add the import.

Leonie B6 — Esc handler in `BulkSelectionBar` was unscoped and stole
Escape from NotificationBell, ConfirmDialog, HelpPopover, etc. (e.g.
selecting docs → opening notification bell → Esc would close the bell
AND silently wipe the selection). Now bails when an open dialog,
expanded menu, or popover is detected.

Elicit C1 — `BulkDocumentEditLayout` topbar now branches on `mode`:
shows "Massenbearbeitung" + "{count} werden bearbeitet" in edit mode
instead of the upload-flavoured "Mehrere Dokumente hochladen" + "werden
erstellt" copy. New i18n keys `bulk_edit_topbar_title` and
`bulk_edit_count_pill` in DE/EN/ES.

Tests added:
 - DocumentControllerTest.patchBulk_stripsCarriageReturnsAndNewlinesFromErrorMessages
   (Sara C2 follow-up — pin sanitizeForLog as a regression test)
 - BulkSelectionBar.spec — count=1 → "1 Dokument", count=2 → "2 Dokumente"
   (Sara C6 follow-up — pin the new bulk_edit_n_selected_one/_other branch)

Refs #225, PR #331

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

frontend/src/lib/components/document/DescriptionSection.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-import { untrack } from 'svelte';
+import { onMount } from 'svelte';
 import TagInput, { type Tag } from '$lib/components/TagInput.svelte';
 import FieldLabelBadge from './FieldLabelBadge.svelte';
 import { m } from '$lib/paraglide/messages.js';
@@ -11,6 +11,7 @@ let {
 	archiveBox = $bindable(''),
 	archiveFolder = $bindable(''),
 	initialTitle = '',
+	initialDocumentLocation = '',
 	initialSummary = '',
 	titleRequired = false,
 	suggestedTitle = '',
@@ -23,6 +24,7 @@ let {
 	archiveBox?: string;
 	archiveFolder?: string;
 	initialTitle?: string;
+	initialDocumentLocation?: string;
 	initialSummary?: string;
 	titleRequired?: boolean;
 	suggestedTitle?: string;
@@ -30,10 +32,17 @@ let {
 	editMode?: boolean;
 } = $props();
 
-// currentTitle seeds from initialTitle once at mount; subsequent edits flow
-// through the oninput handler that flips titleDirty.
+// Seed bindables from initial-* props once at mount and only when the parent
+// hasn't already supplied a non-empty value through the binding. onMount runs
+// exactly once per instance, so this never stomps a parent-driven update on a
+// later prop change. Required by the single-doc edit flow which seeds from
+// the document; bulk-edit consumers leave the initial-* unset and bind their
+// own state.
 let titleDirty = $state(false);
-currentTitle = untrack(() => initialTitle);
+onMount(() => {
+	if (!currentTitle && initialTitle) currentTitle = initialTitle;
+	if (!documentLocation && initialDocumentLocation) documentLocation = initialDocumentLocation;
+});
 const titleValue = $derived(titleDirty ? currentTitle : suggestedTitle || currentTitle);
 </script>