修复scalar_one_or_none相关limit

video-gen-api/app/api/v1/auth.py

@@ -78,7 +78,7 @@ async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
         )
 
     # Check if phone already registered
-    existing = await db.execute(select(User).where(User.phone == req.phone))
+    existing = await db.execute(select(User).where(User.phone == req.phone).limit(1))
     if existing.scalar_one_or_none():
         from fastapi import HTTPException, status
         raise HTTPException(
@@ -89,7 +89,7 @@ async def register(req: RegisterRequest, db: AsyncSession = Depends(get_db)):
     # Create user with default username: 用户 + last 4 digits of phone
     import random
     username = f"用户{req.phone[-4:]}"
-    existing_name = await db.execute(select(User).where(User.username == username))
+    existing_name = await db.execute(select(User).where(User.username == username).limit(1))
     if existing_name.scalar_one_or_none():
         username = f"用户{req.phone[-4:]}{random.randint(10, 99)}"