feat: add fs-backend service

fs-backend/app/main.py

@@ -0,0 +1,40 @@
+"""
+FastAPI 后端服务主入口
+"""
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.core.config import settings
+from app.routers import fs
+
+
+def create_app() -> FastAPI:
+    """创建并配置 FastAPI 应用实例"""
+    app = FastAPI(
+        title="OpenCode Backend API",
+        description="OpenCode 后端服务接口",
+        version="1.0.0",
+    )
+
+    # 配置 CORS
+    app.add_middleware(
+        CORSMiddleware,
+        allow_origins=settings.CORS_ORIGINS,
+        allow_credentials=True,
+        allow_methods=["*"],
+        allow_headers=["*"],
+    )
+
+    # 注册路由
+    app.include_router(fs.router, prefix="/fs", tags=["文件系统"])
+
+    return app
+
+
+app = create_app()
+
+
+@app.get("/")
+async def root():
+    """健康检查接口"""
+    return {"status": "ok", "message": "OpenCode Backend API is running"}