feat: implement async lifespan for FastAPI and remove startup event

backend/app/main.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from contextlib import asynccontextmanager
+
 from fastapi import APIRouter, FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
@@ -22,7 +24,14 @@ from app.db.session import init_db
 
 configure_logging()
 
-app = FastAPI(title="Mission Control API", version="0.1.0")
+
+@asynccontextmanager
+async def lifespan(_: FastAPI):
+    init_db()
+    yield
+
+
+app = FastAPI(title="Mission Control API", version="0.1.0", lifespan=lifespan)
 
 origins = [o.strip() for o in settings.cors_origins.split(",") if o.strip()]
 if origins:
@@ -35,11 +44,6 @@ if origins:
     )
 
 
-@app.on_event("startup")
-def on_startup() -> None:
-    init_db()
-
-
 @app.get("/health")
 def health() -> dict[str, bool]:
     return {"ok": True}

backend/pyproject.toml

@@ -47,3 +47,6 @@ warn_redundant_casts = true
 warn_unused_configs = true
 check_untyped_defs = true
 plugins = ["pydantic.mypy"]
+
+[tool.pytest.ini_options]
+asyncio_default_fixture_loop_scope = "function"