Plugin Control v0.2.1

• Add safe update checks and one action menu for adding, updating, enabling,
  disabling, and removing plugins.
• Add richer marketplace details, activity totals, and on-demand previews.
• Adopt marketplace catalog schema 2 and keep the last usable catalog when a
  source has a recoverable failure.
• Make YAML settings strict and live, including optional background dimming.
• Make submenu keys, focus, status feedback, and settings navigation reliable.
• Restart Omarchy Shell after successful additions and changed updates.
• Keep development symlinks outside automatic update and source-removal paths.