feat(writing): rename module display name "Writing" → "Schreiben"

User-facing label only — keeps the route /writing, the module id
'writing', the appId 'writing', and the table prefix writingDrafts/
writingDraftVersions/etc. Just renames the display name in:
- shared-branding/mana-apps.ts (AppSlider label)
- app-registry/apps.ts (Workbench card label)
- the three writing route <title> tags (page tab in browser)

The English code identity stays; the German UI label gets a German
name consistent with Bibliothek / Kontakte / Kalender / Notizen.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/shared-branding/src/mana-apps.ts

@@ -1073,7 +1073,7 @@ export const MANA_APPS: ManaApp[] = [
 	},
 	{
 		id: 'writing',
-		name: 'Writing',
+		name: 'Schreiben',
 		description: {
 			de: 'KI-Ghostwriter für Texte',
 			en: 'AI ghostwriter for prose',