refactor(auth): remove legacy RESTful user routes and migrate authentication to GraphQL context

- Rename get_current_user to get_current_user_id in auth/deps.py to clarify intent
- Remove legacy /me, /logout routes, and placeholder function from auth/__init__.py
- Remove dependency_overrides from app/main.py
- Update CustomContext to resolve and cache full User objects via db query

app/main.py

@@ -5,7 +5,7 @@ from strawberry import Schema
 from strawberry.fastapi import GraphQLRouter
 from dotenv import load_dotenv
 
-from auth import router as auth_router, get_user_by_id, get_current_user
+from auth import router as auth_router
 
 from app.db import engine, SessionLocal
 from app.models import Base, User
@@ -46,23 +46,7 @@ graphql_router = GraphQLRouter(schema, context_getter=get_context)
 app.include_router(auth_router)                         # 保留现有的 auth 路由供 Google OAuth 回调使用
 app.include_router(graphql_router, prefix="/graphql")   # 挂载 GraphQL 终点，前端以后只需要请求 /graphql
 
-def override_get_user_by_id(user_id: str = Depends(get_current_user)):
-    db = SessionLocal()
-    try:
-        user = db.query(User).filter(User.id == user_id).first()
-        if not user:
-            raise HTTPException(status_code=404, detail="User not found")
-        return {
-            "email": user.email,
-            "name": user.name,
-            "avatar": get_image_url(user.avatar),
-        }
-    finally:
-        db.close()
-        
-app.dependency_overrides[get_user_by_id] = override_get_user_by_id
-
-# test code
+# 打印路由测试
 for route in app.routes:
     methods = getattr(route, "methods", "N/A")
     print(f"Path: {route.path} | Name: {route.name} | Methods: {methods}")