feat : set the time zone for the service

[shootercheng]

Description

set the time zone for the service, with UTC as the default time zone

SERVER_TZ=Asia/Shanghai

Type of Change

• Bug fix
• New feature
• Refactor
• Performance improvement
• Other

Essential Checklist

Testing

• I have tested the changes locally and confirmed they work as expected
• I have added unit tests where necessary and they pass successfully

Bug Fix (if applicable)

• I have used GitHub syntax to close the related issue (e.g., Fixes #123 or Closes #123)

Additional Information

2026-04-07T22:18:31.465134154+08:00 INFO dify-plugin-daemon pool.go:34 init routine pool size=1024
2026-04-07T22:18:31.470927004+08:00 INFO dify-plugin-daemon init.go:120 dify plugin db initialized
2026-04-07T22:18:31.471219729+08:00 INFO dify-plugin-daemon manager.go:118 start plugin manager daemon
2026-04-07T22:18:31.474474739+08:00 INFO dify-plugin-daemon init.go:20 persistence initialized
2026-04-07T22:18:31.474547401+08:00 INFO dify-plugin-daemon server_local.go:16 start to handle new plugins path=plugin

[gemini-code-assist]

Code Review

This pull request introduces support for a configurable server timezone by adding a SERVER_TZ environment variable and updating the configuration logic to set the global time.Local during startup. The logging system was also modified to use local time for record timestamps. Feedback indicates that the initialization sequence in main.go should be re-evaluated, as performing configuration validation and timezone setup before initializing the logger and recovery mechanism may prevent startup errors from being correctly captured and formatted.