feat(#358): W3c — /contacts Sidebar-Sonderfall entfernt (P10)

- ContactsPlugin-Manifest: menu_items + page_routes ergänzt
  (/contacts, /contacts/:id, /contacts/dedup — contacts:read-Gate)
- FrontendMenuItem/FrontendPageRoute-Imports in plugin.py ergänzt
- Sidebar.tsx: /contacts aus singleItems entfernt (nur noch dashboard +
  system-dashboard als non-plugin items) — contacts kommt jetzt via
  getAllMenuItems() aus dem Plugin-Manifest
- Funktionserhalt bewiesen: routePermissions-Tests 6/6 passed
  (die durch die Manifest-Änderung betroffen sein könnten)

fixes #358 (P10-Teil)

app/plugins/builtins/contacts/plugin.py

@@ -11,6 +11,8 @@ import logging
 from app.plugins.base import BasePlugin
 from app.plugins.manifest import (
     FrontendDashboardWidget,
+    FrontendMenuItem,
+    FrontendPageRoute,
     PluginManifest,
     PluginRouteDef,
 )
@@ -70,6 +72,14 @@ class ContactsPlugin(BasePlugin):
                 permission="contacts:read",
             ),
         ],
+        menu_items=[
+            FrontendMenuItem(label_key='nav.contacts', label='Kontakte', path='/contacts', icon='Users', order=10, permission='contacts:read'),
+        ],
+        page_routes=[
+            FrontendPageRoute(path='/contacts', component='@/pages/ContactsList', protected=True, permission='contacts:read'),
+            FrontendPageRoute(path='/contacts/:id', component='@/pages/ContactDetailPage', protected=True, permission='contacts:read'),
+            FrontendPageRoute(path='/contacts/dedup', component='@/pages/DedupMergePage', protected=True, permission='contacts:read'),
+        ],
         permissions=[
             "contacts:read",
             "contacts:write",

frontend/src/components/layout/Sidebar.tsx

@@ -48,12 +48,11 @@ function getIcon(name: string): React.ReactNode {
   return Icon ? <Icon className="h-4 w-4" /> : <FileText className="h-4 w-4" />;
 }
 
-// Only non-plugin items: dashboard, contacts, settings.
+// Only non-plugin items: dashboard, system-dashboard.
-// All other menu entries (calendar, dms, mail, ai-assistant, automation, reports, tasks, communication)
+// All other menu entries (contacts, calendar, dms, mail, ai-assistant, automation, reports, tasks, communication)
 // are provided by plugin manifests via usePluginStore(s => s.getAllMenuItems()).
 const singleItems: NavSingleItem[] = [
   { to: '/dashboard', labelKey: 'nav.dashboard', icon: <Home className="w-5 h-5 flex-shrink-0" aria-hidden="true" strokeWidth={2} />, order: 0 },
-  { to: '/contacts', labelKey: 'nav.contacts', icon: <Users className="w-5 h-5 flex-shrink-0" aria-hidden="true" strokeWidth={2} />, order: 10 },
   { to: '/system-dashboard', labelKey: 'nav.systemDashboard', icon: <Activity className="w-5 h-5 flex-shrink-0" aria-hidden="true" strokeWidth={2} />, order: 90 },
 ];