feat: add foreign key constraints and metrics for blockchain node

apps/blockchain-node/src/aitbc_chain/app.py

@@ -1,24 +1,35 @@
 from __future__ import annotations
 
 from contextlib import asynccontextmanager
-
 from fastapi import APIRouter, FastAPI
 from fastapi.responses import PlainTextResponse
 
 from .config import settings
 from .database import init_db
+from .gossip import create_backend, gossip_broker
 from .metrics import metrics_registry
 from .rpc.router import router as rpc_router
+from .rpc.websocket import router as websocket_router
 
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     init_db()
+    backend = create_backend(
+        settings.gossip_backend,
+        broadcast_url=settings.gossip_broadcast_url,
+    )
+    await gossip_broker.set_backend(backend)
+    try:
+        yield
+    finally:
+        await gossip_broker.shutdown()
+
 
 def create_app() -> FastAPI:
     app = FastAPI(title="AITBC Blockchain Node", version="0.1.0", lifespan=lifespan)
     app.include_router(rpc_router, prefix="/rpc", tags=["rpc"])
-
+    app.include_router(websocket_router, prefix="/rpc")
     metrics_router = APIRouter()
 
     @metrics_router.get("/metrics", response_class=PlainTextResponse, tags=["metrics"], summary="Prometheus metrics")