fix : Plugin table missing for existing PLUGIN_INSTALLED_PATH

[shootercheng]

Description

Fixes #747

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)

[gemini-code-assist]

Code Review

This pull request introduces a check in server_local.go to verify if a plugin's database record exists before launching it. The reviewer pointed out that only the db.ErrDatabaseNotFound error is handled, meaning other database errors (such as connection timeouts or query failures) are silently ignored, which could allow the plugin to launch in an inconsistent state. The reviewer suggested handling all non-nil errors and logging them appropriately.