feat: scaffold modular monolith backend architecture

app/main.py

@@ -0,0 +1,39 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+from contextlib import asynccontextmanager
+from app.config import settings
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    # 启动时：初始化 DB 连接池、Redis 事件总线与外部适配器
+    print(f"Starting {settings.PROJECT_NAME} in [{settings.ENVIRONMENT}] mode...")
+    yield
+    # 关闭时：优雅断开连接
+    print(f"Shutting down {settings.PROJECT_NAME}...")
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    version=settings.VERSION,
+    lifespan=lifespan,
+    docs_url="/docs" if settings.ENVIRONMENT != "production" else None,
+    redoc_url="/redoc" if settings.ENVIRONMENT != "production" else None
+)
+
+# CORS 配置
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=settings.CORS_ORIGINS,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+@app.get("/health", tags=["System"])
+async def health_check():
+    """生产探活与健康检查端点 (Blue-Green Probe)"""
+    return {
+        "status": "ok",
+        "service": "wtfx-backend",
+        "version": settings.VERSION,
+        "environment": settings.ENVIRONMENT
+    }