### What problem does this PR solve?
The Profile **Name** field currently lacks application-level validation
and allows users to save excessively long names and unsupported special
characters.
While the database enforces a maximum length of 100 characters, neither
the frontend nor backend validates nickname format before persistence.
This can result in inconsistent user data, poor user experience, and UI
layout issues when long names wrap across multiple lines.
This PR introduces consistent frontend and backend validation for
profile names, enforces length and character constraints, provides clear
validation feedback, and prevents invalid values from being saved.
Fixes#15693
### Type of change
* [x] Bug Fix (non-breaking change which fixes an issue)
### 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
