Implement Phase 1: LangGraph backend MVP

Sets up the full backend foundation for CouncilOS:

- CouncilState TypedDict with all required fields and LangGraph reducers
- Three agent nodes: master_agent (drafts), critic_agent (scores + routes),
  writer_agent (final polish)
- LangGraph graph with cyclic rework loop: Master → Critic → (score < 8:
  back to Master | score ≥ 8: Writer → END)
- Safety valve: MAX_ITERATIONS=5 prevents infinite loops
- FastAPI app with REST endpoints (POST /api/councils/run, GET /api/councils/run/{id})
  and WebSocket endpoint (/ws/council/{run_id}) for real-time agent status events
- In-memory RunStore for Phase 1 (PostgreSQL-backed in Phase 3)
- pytest test suite: state, routing logic, critic parser, agent nodes, API endpoints
- .env.example, .gitignore, docker-compose.yml, Dockerfile

https://claude.ai/code/session_01RfMpt3TbMjZEtK3CAyP5iQ

backend/api/run_store.py

@@ -0,0 +1,47 @@
+"""
+In-memory run store for Phase 1.
+
+Tracks the status and results of council runs by run_id. This is intentionally
+simple for Phase 1. Phase 3+ will replace this with a PostgreSQL-backed store.
+"""
+
+from typing import Any, Dict, Optional
+import threading
+
+
+class RunStore:
+    """Thread-safe in-memory store for council run state."""
+
+    def __init__(self) -> None:
+        self._store: Dict[str, Dict[str, Any]] = {}
+        self._lock = threading.Lock()
+
+    def create(self, run_id: str, input_topic: str) -> None:
+        with self._lock:
+            self._store[run_id] = {
+                "run_id": run_id,
+                "input_topic": input_topic,
+                "status": "pending",
+                "final_draft": None,
+                "critic_score": None,
+                "iteration_count": None,
+                "active_node": None,
+                "error": None,
+            }
+
+    def get(self, run_id: str) -> Optional[Dict[str, Any]]:
+        with self._lock:
+            return self._store.get(run_id)
+
+    def update(self, run_id: str, updates: Dict[str, Any]) -> None:
+        with self._lock:
+            if run_id in self._store:
+                self._store[run_id].update(updates)
+
+    def delete(self, run_id: str) -> None:
+        with self._lock:
+            self._store.pop(run_id, None)
+
+
+# Singleton instance shared across the application
+run_store = RunStore()