feat(auth): integrate Google OAuth2 and secure cookie management

- Configured CORS middleware to allow cross-origin requests from the frontend.
- Implemented Google OAuth2 login flow and post-auth frontend redirection.
- Managed secure HTTP-only cookies for access, refresh, and state tokens.

app/main.py

@@ -1,4 +1,6 @@
+import os
 from fastapi import FastAPI, Depends, HTTPException
+from fastapi.middleware.cors import CORSMiddleware
 from strawberry import Schema
 from strawberry.fastapi import GraphQLRouter
 
@@ -19,6 +21,19 @@ Base.metadata.create_all(bind=engine)
 # 创建 FastAPI 实例
 app = FastAPI()
 
+# 获取环境变量字符串，并转成列表
+origins_str = os.getenv("CORS_ORIGINS", "http://localhost:3000")
+origins = [origin.strip() for origin in origins_str.split(",")]
+
+# 配置 CORS 中间件，允许前端访问
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=origins,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
 # 组装 GraphQL Schema
 schema = Schema(query=Query, mutation=Mutation)