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/main.py

@@ -0,0 +1,59 @@
+"""
+CouncilOS — FastAPI application entrypoint.
+
+Start the server:
+    uvicorn main:app --reload --port 8000
+
+API Overview:
+    POST /api/councils/run          — Start a council run
+    GET  /api/councils/run/{run_id} — Poll run status/result
+    GET  /api/health                — Health check
+    WS   /ws/council/{run_id}       — Real-time agent status events
+"""
+
+from contextlib import asynccontextmanager
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from api.routes import router
+from api.websocket import ws_router
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """Application lifespan: startup and shutdown logic."""
+    print("CouncilOS API starting up...")
+    yield
+    print("CouncilOS API shutting down...")
+
+
+app = FastAPI(
+    title="CouncilOS API",
+    description=(
+        "Backend for the CouncilOS multi-agent AI pipeline platform. "
+        "Orchestrates LangGraph council runs and streams real-time agent "
+        "status via WebSockets."
+    ),
+    version="0.1.0",
+    lifespan=lifespan,
+)
+
+# CORS — allow all origins in development; tighten in production
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Mount REST routes under /api prefix
+app.include_router(router, prefix="/api")
+
+# Mount WebSocket routes (no prefix — path is /ws/council/{run_id})
+app.include_router(ws_router)
+
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)