Restructure into full project layout

backend/app/main.py

@@ -0,0 +1,36 @@
+from contextlib import asynccontextmanager
+
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.core.database import engine, Base
+from app.core.admin_bootstrap import bootstrap_admin
+from app.api.routes import auth, users, admin, decks, collection
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    await bootstrap_admin()
+    yield
+
+
+app = FastAPI(title="MTG Deck Builder", version="1.0.0", lifespan=lifespan)
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+app.include_router(auth.router, prefix="/api/auth", tags=["auth"])
+app.include_router(users.router, prefix="/api/users", tags=["users"])
+app.include_router(admin.router, prefix="/api/admin", tags=["admin"])
+app.include_router(decks.router, prefix="/api/decks", tags=["decks"])
+app.include_router(collection.router, prefix="/api/collection", tags=["collection"])
+
+
+@app.get("/api/health")
+async def health():
+    return {"status": "ok"}