Implement Phase 3: dynamic graph builder, blueprint persistence, and CRUD API

- Add dynamic_graph_builder.py that constructs LangGraph graphs at runtime
  from frontend CouncilBlueprint JSON (no more hardcoded graphs in production)
- Add PostgreSQL persistence via SQLAlchemy async with Blueprint model
- Add blueprint CRUD endpoints (POST/GET/PUT/DELETE /api/councils/)
- Add POST /api/councils/{id}/run to execute blueprints dynamically
- Add Alembic migration infrastructure with initial blueprints table
- Add database.py with async engine and SQLite fallback for dev/test
- Fix missing typing-extensions and add aiosqlite dependency
- Add 42 new tests (80/80 total passing) covering dynamic graph building,
  blueprint service CRUD, and API integration

https://claude.ai/code/session_014yZUxrPsgZbvkebXbCXR4U

backend/main.py

@@ -5,10 +5,16 @@ 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
+    POST   /api/councils/              — Create a blueprint
+    GET    /api/councils/              — List all blueprints
+    GET    /api/councils/{id}          — Get specific blueprint
+    PUT    /api/councils/{id}          — Update a blueprint
+    DELETE /api/councils/{id}          — Delete a blueprint
+    POST   /api/councils/run           — Start a run (Phase 1 hard-coded graph)
+    POST   /api/councils/{id}/run      — Start a run from a blueprint (Phase 3)
+    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
@@ -16,14 +22,19 @@ from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
 from api.routes import router
+from api.blueprint_routes import blueprint_router
 from api.websocket import ws_router
+from database import init_db, close_db
 
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     """Application lifespan: startup and shutdown logic."""
     print("CouncilOS API starting up...")
+    await init_db()
+    print("Database initialized.")
     yield
+    await close_db()
     print("CouncilOS API shutting down...")
 
 
@@ -34,7 +45,7 @@ app = FastAPI(
         "Orchestrates LangGraph council runs and streams real-time agent "
         "status via WebSockets."
     ),
-    version="0.1.0",
+    version="0.2.0",
     lifespan=lifespan,
 )
 
@@ -49,6 +60,7 @@ app.add_middleware(
 
 # Mount REST routes under /api prefix
 app.include_router(router, prefix="/api")
+app.include_router(blueprint_router, prefix="/api")
 
 # Mount WebSocket routes (no prefix — path is /ws/council/{run_id})
 app.include_router(ws_router)