### What this PR fixes
This PR fixes an issue in the Python backend where user logout did not
reliably persist the invalidated access_token to the database.
Although the logout endpoint returned success and logged that the token
had been invalidated, the user.access_token value could remain
unchanged in the database, which meant the previous login token could
stay valid longer than expected.
### What changed
- Resolve the real user object before updating the token
- Persist the invalidated access_token before calling logout_user()
- Return a server error if the token update is not written successfully
### Impact
- Logging out now correctly replaces the stored access_token with an
INVALID_... value
- The previous login session is properly invalidated
- The change is limited to the logout flow and is intentionally small in
scope
### What problem does this PR solve?
Python implementation of the Go-based model_provider API suite.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
---------
Co-authored-by: bill <yibie_jingnian@163.com>
Closes#14789
### What problem does this PR solve?
User API endpoints (`login`, `user_profile`, `user_add`,
`forget_reset_password`) were returning full user objects via
`to_json()` / `to_dict()`, which included sensitive fields like
`password` and `access_token` in the response body. This leaks
credentials to the client.
This PR adds a `to_safe_dict()` method on the `User` model that strips
sensitive fields (`password`, `access_token`) and replaces all affected
call sites to use it.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
- Moved if not all([email, new_pwd, new_pwd2]) guard to the top, before
any decryption that could crash on None value
- Removed the redundant REDIS_CONN.get() call — one call is sufficient
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] Refactoring
