feat: unified_search + ai_proactive plugins with Ollama Cloud DeepSeek V4

- unified_search: Hybride Suche (PostgreSQL FTS + pgvector + RRF Fusion)
  - 5 Search Providers (Contact, Company, Mail, File, Event)
  - KI Query Understanding (Fuzzy, Facetten via LiteLLM)
  - DMS Text-Extraction (PDF, DOCX, XLSX, PPTX)
  - Embedding Pipeline (ollama/nomic-embed-text, 768 Dim)
  - Background Jobs für Indexierung
  - Plugin-basierte Provider Registry

- ai_proactive: Proaktiver KI-Agent
  - Context-Tracking (Frontend → Backend → Event Bus)
  - Proactive Engine mit LLM Suggestion-Generierung
  - SSE Real-time Push an Frontend
  - 6 AI Tools für Tool Registry
  - Rate-Limiting + User Settings
  - Deep Analysis Background Jobs

- Frontend Integration:
  - useAIContext Hook, SuggestionSidebar, SuggestionBadge
  - ProactiveAISettings Page, Search API Client
  - Globale Suche auf neue API umgestellt

- Tests: test_unified_search.py + test_ai_proactive.py (alle bestanden)
- Config: Ollama Cloud DeepSeek V4 als Default, konfigurierbar
- Dependencies: PyMuPDF, python-docx, python-pptx, pgvector
- Bugfixes: notification type_key length, migration IF NOT EXISTS

frontend/src/components/layout/TopBar.tsx

@@ -9,12 +9,13 @@ import { useLogout } from '@/api/hooks';
 import { Avatar } from '@/components/ui/Avatar';
 import { Badge } from '@/components/ui/Badge';
 import { SearchDropdown } from '@/components/shared/SearchDropdown';
+import { SuggestionBadge } from '@/components/ai/SuggestionBadge';
 
 export function TopBar() {
   const { t } = useTranslation();
   const navigate = useNavigate();
   const { user } = useAuthStore();
-  const { toggleSidebar, toggleAISidebar, aiSidebarCollapsed } = useUIStore();
+  const { toggleSidebar, toggleAISidebar, toggleSuggestionSidebar, aiSidebarCollapsed } = useUIStore();
   const { currentTenant, availableTenants, switchTenant, isSwitching } = useTenant();
   const logoutMutation = useLogout();
 
@@ -141,6 +142,9 @@ export function TopBar() {
       </div>
 
       <div className="flex items-center gap-2">
+        {/* AI Suggestions Badge */}
+        <SuggestionBadge onClick={toggleSuggestionSidebar} />
+
         {/* Notifications */}
         <div ref={notifRef} className="relative">
           <button