- Added metadata merge helpers in `sdk/cliproxy/auth` to retain existing auth-file settings while excluding token lifecycle fields.
- Applied merge before saving in management handler and `sdk/auth.Manager.Login` so re-login overwrites credentials without discarding user-configured fields.
- Updated token save paths for Claude, Codex, Kimi, XAI, and Vertex to persist merged metadata payloads when writing auth files.
Closes: #4945
- Implemented a global logger with structured formatting for consistent log output.
- Added support for rotating log files using Lumberjack.
- Integrated new logging functionality with Gin HTTP server for unified log handling.
- Replaced direct `log.Info` calls with `fmt.Printf` in non-critical paths to simplify core functionality.
The logic for logging the path where credentials are saved was duplicated across several client implementations.
This commit refactors this behavior by creating a new centralized function, `misc.LogSavingCredentials`, to handle this logging. The `SaveTokenToFile` method in each authentication token storage struct now calls this new function, ensuring consistent logging and reducing code duplication.
The redundant logging statements in the client-level `SaveTokenToFile` methods have been removed.
