Merge feature/inbox-1: Anfragen-Posteingang UI (list/triage/assign/draft/send) [god-QA pending]

# Conflicts:
#	gerbil-manager-web/e2e/mock-data.ts
#	gerbil-manager-web/src/App.tsx

gerbil-manager-web/src/components/AppShell.tsx

@@ -22,6 +22,8 @@ const SECONDARY: NavItem[] = [
   { to: '/becken', label: de.nav.enclosures, icon: '🛁' },
   { to: '/kontakte', label: de.nav.contacts, icon: '📇' },
   { to: '/abgabe', label: de.nav.forSale, icon: '🏡' },
+  // INBOX-1: Anfragen-Posteingang
+  { to: '/anfragen', label: de.nav.requests, icon: '📨' },
   { to: '/statistik', label: de.nav.statistics, icon: '📊' },
   // FEAT-13: Abgabeverträge + Zuchtprofil
   { to: '/vertraege', label: de.nav.contracts, icon: '📄' },