INBOX-1: Anfragen-Posteingang UI - Liste (Status-Filter, Sync-Button mit MailNotConfigured-Hinweis), Detail (Triage/Zuordnen/Verwerfen, KI-Entwurf mit AiKeyMissing-Hinweis, bestaetigter Versand) + nav + 6 e2e-Specs (Mock um /api/requests erweitert)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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: '📄' },