WIP checkpoint: Scaffold FastAPI backend project structure

backend/app/main.py

@@ -0,0 +1,36 @@
+"""FastAPI application entry point."""
+
+from contextlib import asynccontextmanager
+
+from fastapi import FastAPI
+
+from app.config import settings
+from app.routers import auth, users, worlds, assets
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """Application lifespan: startup and shutdown events."""
+    # Startup: initialize database, connect to Redis, etc.
+    yield
+    # Shutdown: close connections, cleanup
+
+
+app = FastAPI(
+    title=settings.app_name,
+    version=settings.app_version,
+    description="Agentic Game Platform - Backend API",
+    lifespan=lifespan,
+)
+
+# Include routers
+app.include_router(auth.router, prefix="/api/auth", tags=["auth"])
+app.include_router(users.router, prefix="/api/users", tags=["users"])
+app.include_router(worlds.router, prefix="/api/worlds", tags=["worlds"])
+app.include_router(assets.router, prefix="/api/assets", tags=["assets"])
+
+
+@app.get("/api/health")
+async def health_check():
+    """Simple health check endpoint."""
+    return {"status": "ok", "app": settings.app_name}