Pages reconcile could succeed while agent state retained a previous
network error, so health events stayed active indefinitely. Clear
LastError whenever sync completes successfully without re-applying
config, and cover the paths with regression tests.
- Implement configurable FRPS WebUI switch and custom port setting (relay_frps_web_ui_port) in system configs.
- Integrate settings into Relay Node detail manage page instead of global settings.
- Dynamically query server version to select matching Docker image tag for Relay installation.
- Clean up legacy code and fix backend linter/test warnings.