feat(plugins): plugin service restart & schema migration

[bekmuradov]

• Added new Alembic migration 9f65d0e59c6f:
  • Creates plugin_service_runtime table with definition_id,
    and environment variable support.
• Backend changes:
  • Created restart_plugin_services for consistent service lifecycle handling.
  • Added start_plugin_services_from_settings_on_startup
    to restart services on backend startup/restart.
  • Updated plugin repository with get_service_runtimes_by_plugin_id and
    get_settings_env_vars.
  • Changed plugin installation flow to run service runtime setup in background,
    reducing install timeouts.
• Frontend changes:
  • Added Plugin Settings component to manage plugin service runtime environment
    variables with better UX/UI:
    • Improved form layout and validation to reduce input mistakes.
    • Easier editing and restarting of plugin services from UI.
  • Updated restart handler to expect new API response (success/message).
• General improvements:
  • Grouped service restarts by (plugin_slug, definition_id) to avoid duplicates.
  • Improved logging around service installation and startup.