Implement Phase 4: tools, God Mode, and missing features

Backend:
- Add Tavily web search tool wrapper (tools/web_search.py)
- Add PDF reader + ChromaDB vector store tool (tools/pdf_reader.py)
- Bind tools to LLM calls via .bind_tools() in dynamic_graph_builder
- Implement God Mode using LangGraph interrupt_before + MemorySaver
- Add approve/reject/modify API endpoints for God Mode
- Add PDF upload endpoint with ingestion pipeline
- Add persistent run history (CouncilRun model + run_service + API)
- Add Alembic migration for council_runs table
- Enhance WebSocket to emit run_paused and run_resumed events
- Add tests for tools, God Mode, and run history

Frontend:
- Add God Mode approval UI (GodModePanel component)
- Add Auto-Pilot / God Mode toggle in Konferenzzimmer
- Add functional PDF upload handler
- Add Conditional Edge editor (EdgeSettingsPanel component)
- Add edge click selection in ArchitectCanvas
- Update Zustand store with edge selection and update actions
- Update types for God Mode, execution modes, and WS events
- Update API client with God Mode, PDF upload, and blueprint run endpoints
- Update WebSocket hook for paused/resumed events
- Add Vitest config and frontend tests (store, parser, types, API)

https://claude.ai/code/session_017U6idFgaqnYTXzPxA7mxMv

backend/database.py

@@ -38,6 +38,7 @@ async def get_session() -> AsyncSession:
 async def init_db() -> None:
     """Create all tables. Used at application startup."""
     from models.blueprint import Base
+    import models.council_run  # noqa: F401 — register CouncilRun model
 
     async with engine.begin() as conn:
         await conn.run_sync(Base.metadata.create_all)