feat(delegations): UI fuer Berechtigungs-Delegationen — Modul 2/16 des UI-Backlogs

Backend existierte vollstaendig (5 Endpoints: list/create/update/delete/
active-check, delegations:read/write seit Audit-Fix im Katalog), Frontend
hatte 0% Abdeckung. Modul folgt dem Approvals-Muster (Modul 1):

- api/delegations.ts: TanStack-Hooks (useDelegations mit direction-Filter,
useActiveDelegations, create/update/delete-Mutations mit Cache-Invalidierung)
- pages/Delegations.tsx: Richtungstabs (alle/von mir/an mich), Karten mit
  Phasen-Badges (aktiv/geplant/abgelaufen/inaktiv), Erstellen-Dialog mit
  Empfaenger-Picker (useUsers, sich selbst ausschliessend), Start/Ende-
  Datetime, Scope-Toggle (alle Berechtigungen), Aktivieren/Deaktivieren,
  Loeschen mit Confirm — Aktionen hinter delegations:write gegated
- Route /delegations (PermissionRoute delegations:read) — als Core-Route
  bewusst statisch registriert (Phase-Q-Regel: nur Plugin-Routen laufen
  ueber Manifeste) Sidebar-Entry order 92 (ArrowRightLeft-Icon)
- i18n delegations.* + nav.delegations de/en

Verifikation: Vitest 9/9 (Rendering, Tabs, Phasen, Permission-Gating,
Create-Flow, Toggle, Delete) · tsc exit 0 · production build exit 0.

frontend/src/i18n/locales/de.json

@@ -22,7 +22,8 @@
     "tasks": "Aufgaben",
     "wiki": "Wiki",
     "systemDashboard": "System Dashboard",
-    "approvals": "Freigaben"
+    "approvals": "Freigaben",
+    "delegations": "Delegationen"
   },
   "auth": {
     "login": "Anmelden",
@@ -1631,5 +1632,32 @@
     "requesterUser": "Benutzer",
     "requesterAgent": "Agent",
     "requesterSystem": "System"
+  },
+  "delegations": {
+    "title": "Delegationen",
+    "tabAll": "Alle",
+    "tabFrom": "Von mir vergeben",
+    "tabTo": "An mich vergeben",
+    "create": "Delegation erstellen",
+    "createTitle": "Berechtigungen delegieren",
+    "createSubmit": "Delegieren",
+    "recipient": "Empfaenger",
+    "recipientPlaceholder": "Benutzer auswaehlen",
+    "startAt": "Beginn",
+    "endAt": "Ende",
+    "scopeAll": "Alle Berechtigungen delegieren",
+    "cardTo": "An {{user}}",
+    "cardFrom": "Von {{user}}",
+    "period": "Zeitraum:",
+    "phase_active": "Aktiv",
+    "phase_upcoming": "Geplant",
+    "phase_expired": "Abgelaufen",
+    "phase_inactive": "Inaktiv",
+    "activate": "Aktivieren",
+    "deactivate": "Deaktivieren",
+    "delete": "Loeschen",
+    "deleteConfirm": "Diese Delegation wirklich loeschen?",
+    "empty": "Keine Delegationen in dieser Ansicht.",
+    "loadError": "Delegationen konnten nicht geladen werden."
   }
 }

frontend/src/i18n/locales/en.json

@@ -22,7 +22,8 @@
     "tasks": "Tasks",
     "wiki": "Wiki",
     "systemDashboard": "System Dashboard",
-    "approvals": "Approvals"
+    "approvals": "Approvals",
+    "delegations": "Delegations"
   },
   "auth": {
     "login": "Sign In",
@@ -1631,5 +1632,32 @@
     "requesterUser": "User",
     "requesterAgent": "Agent",
     "requesterSystem": "System"
+  },
+  "delegations": {
+    "title": "Delegations",
+    "tabAll": "All",
+    "tabFrom": "Given by me",
+    "tabTo": "Given to me",
+    "create": "Create delegation",
+    "createTitle": "Delegate permissions",
+    "createSubmit": "Delegate",
+    "recipient": "Recipient",
+    "recipientPlaceholder": "Select a user",
+    "startAt": "Start",
+    "endAt": "End",
+    "scopeAll": "Delegate all permissions",
+    "cardTo": "To {{user}}",
+    "cardFrom": "From {{user}}",
+    "period": "Period:",
+    "phase_active": "Active",
+    "phase_upcoming": "Upcoming",
+    "phase_expired": "Expired",
+    "phase_inactive": "Inactive",
+    "activate": "Activate",
+    "deactivate": "Deactivate",
+    "delete": "Delete",
+    "deleteConfirm": "Really delete this delegation?",
+    "empty": "No delegations in this view.",
+    "loadError": "Failed to load delegations."
   }
 }