fix(korrespondenz): dark theme, compact strip labels, year divider size, chevron alignment

- Add compact prop to PersonTypeahead: 7px uppercase label, 30px h input (matches spec FL/FI)
- Replace all hardcoded hex in 6 korrespondenz components with theme tokens (bg-surface,
  bg-muted, bg-canvas, border-line, text-ink, text-primary, text-accent, etc.)
- Fix year divider: text-[15px] font-black (spec: 15px/900)
- Fix log row chevron: items-center instead of items-start for vertical centering
- Fix recent-persons persistence: move persistRecentPerson to post-navigation $effect so
  senderName is resolved from server before stored in localStorage
- Add metadataComplete field to makeDoc() fixture to satisfy updated Document type
- Restore opacity-0 on swap button when only one person is set (matches spec + test)

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

frontend/src/routes/korrespondenz/page.svelte.spec.ts

@@ -37,6 +37,7 @@ const makeDoc = (overrides: Record<string, unknown> = {}) => ({
 	status: 'UPLOADED' as const,
 	documentDate: '1923-04-12',
 	location: 'Berlin',
+	metadataComplete: false,
 	sender: { id: 'p1', firstName: 'Hans', lastName: 'Müller' },
 	receivers: [{ id: 'p2', firstName: 'Anna', lastName: 'Schmidt' }],
 	tags: [],