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/tools/web_search.py

@@ -0,0 +1,61 @@
+"""
+Web Search Tool — Tavily Search API wrapper for agent nodes.
+
+Provides a LangChain-compatible tool that agents can use to search the web
+for current information. Requires the TAVILY_API_KEY environment variable.
+"""
+
+import os
+from typing import Optional
+
+from langchain_core.tools import tool
+
+
+@tool
+def web_search(query: str, max_results: int = 5) -> str:
+    """
+    Search the web for current information on a topic.
+
+    Args:
+        query: The search query string.
+        max_results: Maximum number of results to return (default 5).
+
+    Returns:
+        A formatted string with search results including titles, URLs, and snippets.
+    """
+    from tavily import TavilyClient
+
+    api_key = os.environ.get("TAVILY_API_KEY")
+    if not api_key:
+        return "[Web Search Error] TAVILY_API_KEY environment variable is not set."
+
+    client = TavilyClient(api_key=api_key)
+
+    try:
+        response = client.search(
+            query=query,
+            max_results=max_results,
+            search_depth="basic",
+        )
+    except Exception as exc:  # noqa: BLE001
+        return f"[Web Search Error] {exc}"
+
+    results = response.get("results", [])
+    if not results:
+        return f"No results found for: {query}"
+
+    formatted = []
+    for i, r in enumerate(results, 1):
+        title = r.get("title", "No title")
+        url = r.get("url", "")
+        content = r.get("content", "No content available")
+        formatted.append(f"{i}. **{title}**\n   URL: {url}\n   {content}")
+
+    return "\n\n".join(formatted)
+
+
+def create_web_search_tool() -> Optional[tool]:
+    """Factory that returns the web_search tool if Tavily is configured."""
+    if os.environ.get("TAVILY_API_KEY"):
+        return web_search
+    return None