Reparaturplan Fixes: Widget workspace_id check, total bug, context is_visible, permissions, fallbacks

Backend:
- Widget total: 0 bug fixed (now returns len(widgets))
- Widget update/delete: now verifies workspace_id + tenant_id (was only tenant_id)
- Workspace context: returns all modules with is_visible flag (was only visible modules)
- is_workspace_manager() removed (Plan 4.2: no manager checks)
- seed_default_workspace: removed hardcoded modules (Plan 4.7: no hardcoded tiles)
- Workspace permissions registered in CORE_PERMISSIONS (Plan 2.3)

Frontend:
- Permission fallback removed: Sidebar/TopBar show nothing while loading (Plan 2.4)
- workspaceStore isModuleVisible: fail-closed when isSystemAdmin undefined
- WorkspaceManager: AVAILABLE_MODULES replaced with dynamic core+plugin items (Plan 4.4)

Tests:
- 17 backend tests (removed is_workspace_manager test, adapted widget/context tests)
- 13 frontend tests (added undefined-isSystemAdmin test, adapted visibility tests)

frontend/src/components/layout/Sidebar.tsx

@@ -70,8 +70,8 @@ export function Sidebar() {
   // Use hasPermission directly — permissions are loaded via useUserPermissions hook
   const canAccess = (perm?: string): boolean => {
     if (!perm) return true;
-    // While permissions are loading (undefined), show everything; backend 403 catches errors
-    if (!user?.permissions && user?.is_system_admin === undefined) return true;
+    // While permissions are loading (undefined), show nothing for protected items
+    if (!user?.permissions && user?.is_system_admin === undefined) return false;
     return hasPermission(perm);
   };
 

frontend/src/components/layout/TopBar.tsx

@@ -25,7 +25,7 @@ export function TopBar() {
   const { hasPermission } = usePermission();
   // While permissions are loading (undefined), show everything; backend 403 catches errors
   const canAccess = (perm: string): boolean => {
-    if (!user?.permissions && user?.is_system_admin === undefined) return true;
+    if (!user?.permissions && user?.is_system_admin === undefined) return false;
     return hasPermission(perm);
   };
   const restoreWindow = useWindowStore((s) => s.restoreWindow);

frontend/src/components/settings/WorkspaceManager.tsx

@@ -1,21 +1,13 @@
-import { useState } from 'react';
+import { useState, useMemo } from 'react';
 import { useTranslation } from 'react-i18next';
 import { useWorkspaces, useCreateWorkspace, useUpdateWorkspace, useDeleteWorkspace, useSetWorkspaceModules, useAssignWorkspaceUser, useRemoveWorkspaceUser, type Workspace, type WorkspaceModule } from '@/api/hooks/workspaces';
+import { usePluginStore } from '@/store/pluginStore';
 import { LayoutGrid, Plus, Trash2, Edit, Users, Save, X, Check } from 'lucide-react';
 
-const AVAILABLE_MODULES = [
-  { key: 'contacts', label: 'Kontakte' },
-  { key: 'calendar', label: 'Kalender' },
-  { key: 'mail', label: 'E-Mail' },
-  { key: 'tasks', label: 'Aufgaben' },
-  { key: 'dms', label: 'Dokumente' },
-  { key: 'kommunikation', label: 'Kommunikation' },
-  { key: 'reports', label: 'Reports' },
-  { key: 'automation', label: 'Automation' },
-  { key: 'tags', label: 'Tags' },
+// Static core menu items — same as Sidebar.tsx
+const CORE_MENU_ITEMS = [
   { key: 'dashboard', label: 'Dashboard' },
-  { key: 'settings', label: 'Einstellungen' },
-  { key: 'audit', label: 'Audit-Log' },
+  { key: 'contacts', label: 'Kontakte' },
 ];
 
 export function WorkspaceManager() {
@@ -25,6 +17,24 @@ export function WorkspaceManager() {
   const updateWs = useUpdateWorkspace();
   const deleteWs = useDeleteWorkspace();
   const setModules = useSetWorkspaceModules();
+  const manifests = usePluginStore(s => s.manifests);
+
+  // Dynamically build available modules from core menu items + plugin manifests
+  const availableModules = useMemo(() => {
+    const pluginItems = manifests
+      .flatMap(m => m.menu_items || [])
+      .map(item => ({
+        key: item.path.replace(/^\//, '').split('/')[0],
+        label: item.label || item.label_key,
+      }));
+    // Merge core + plugin, deduplicate by key
+    const seen = new Set<string>();
+    return [...CORE_MENU_ITEMS, ...pluginItems].filter(m => {
+      if (seen.has(m.key)) return false;
+      seen.add(m.key);
+      return true;
+    });
+  }, [manifests]);
 
   const [showCreate, setShowCreate] = useState(false);
   const [editingId, setEditingId] = useState<string | null>(null);
@@ -59,7 +69,7 @@ export function WorkspaceManager() {
   const openModuleEditor = (ws: Workspace) => {
     setModuleWsId(ws.id);
     const existing = ws.modules || [];
-    setModuleConfig(AVAILABLE_MODULES.map(m => {
+    setModuleConfig(availableModules.map(m => {
       const existingMod = existing.find(e => e.module_key === m.key);
       return {
         module_key: m.key,
@@ -144,7 +154,7 @@ export function WorkspaceManager() {
           </div>
           <div className="grid grid-cols-2 md:grid-cols-3 gap-2">
             {moduleConfig.map(m => {
-              const mod = AVAILABLE_MODULES.find(a => a.key === m.module_key);
+              const mod = availableModules.find(a => a.key === m.module_key);
               return (
                 <label key={m.module_key} className="flex items-center gap-2 p-2 border border-gray-200 dark:border-gray-700 rounded-md cursor-pointer hover:bg-gray-50 dark:hover:bg-gray-800">
                   <input