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/WhoWhenSection.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-import { untrack } from 'svelte';
+import { onMount, untrack } from 'svelte';
 import PersonTypeahead from '$lib/components/PersonTypeahead.svelte';
 import PersonMultiSelect from '$lib/components/PersonMultiSelect.svelte';
 import FieldLabelBadge from './FieldLabelBadge.svelte';
@@ -13,6 +13,8 @@ let {
 	senderId = $bindable(''),
 	selectedReceivers = $bindable<Person[]>([]),
 	dateIso = $bindable(''),
+	initialDateIso = '',
+	initialLocation = '',
 	initialSenderName = '',
 	suggestedDateIso = '',
 	suggestedSenderName = '',
@@ -22,6 +24,8 @@ let {
 	senderId?: string;
 	selectedReceivers?: Person[];
 	dateIso?: string;
+	initialDateIso?: string;
+	initialLocation?: string;
 	initialSenderName?: string;
 	suggestedDateIso?: string;
 	suggestedSenderName?: string;
@@ -29,11 +33,20 @@ let {
 	editMode?: boolean;
 } = $props();
 
-// Seed dateDisplay from the bindable's current value once at mount; subsequent
-// edits flow through handleDateInput which writes back to dateIso.
-let dateDisplay = $state(untrack(() => isoToGerman(dateIso)));
+// dateDisplay seeds from the bindable's value or initialDateIso once at mount
+// and is then user-driven. onMount runs exactly once, so this never stomps
+// the parent's dateIso on a later prop change.
+let dateDisplay = $state('');
 let dateDirty = $state(false);
 
+onMount(() => {
+	const seed = dateIso || initialDateIso;
+	if (seed) {
+		dateDisplay = isoToGerman(seed);
+		if (!dateIso) dateIso = seed;
+	}
+});
+
 const dateInvalid = $derived(dateDirty && dateDisplay.length > 0 && dateIso === '');
 
 function handleDateInput(e: Event) {
@@ -119,6 +132,7 @@ $effect(() => {
 					id="location"
 					type="text"
 					name="location"
+					value={initialLocation}
 					placeholder={m.form_placeholder_location()}
 					class="block w-full rounded border border-line px-2 py-3 text-sm shadow-sm focus:outline-none focus-visible:ring-2 focus-visible:ring-focus-ring"
 				/>