Add discord_id and profile_picture to user schemas, add UserAdminUpdate for admin actions

backend/app/schemas/user.py

@@ -8,6 +8,8 @@ class UserBase(BaseModel):
     username: str
     email: str  # Changed from EmailStr to allow .local domains for home networks
     full_name: Optional[str] = None
+    discord_id: Optional[str] = None
+    profile_picture: Optional[str] = None
 
 class UserCreate(UserBase):
     """Schema for creating a user."""
@@ -17,9 +19,15 @@ class UserUpdate(BaseModel):
     """Schema for updating a user."""
     email: Optional[str] = None
     full_name: Optional[str] = None
+    discord_id: Optional[str] = None
+    profile_picture: Optional[str] = None
     password: Optional[str] = None
     is_active: Optional[bool] = None
 
+class UserAdminUpdate(UserUpdate):
+    """Schema for admin updating a user (includes admin-only fields)."""
+    is_admin: Optional[bool] = None
+
 class UserResponse(UserBase):
     """Schema for user response."""
     id: int