Admin only tags 1.0.0

This is my first addon, please be gentle.

What it does:
AdminOnlyTags lets you mark individual tags for admin-only use, so non-admin users can't apply them to any content.

Features:
- Restricts individual tags to admin-only use from a dedicated admin panel page or the tag editing form.
- Hides restricted tags from user autocomplete
- Error message when non-admin users try to use restricted tags

Why it exists:
I wanted a way to reserve certain tags for admin purposes (like "announcement", "verified", etc.) without
completely locking down the tagging system.

Technical stuff:
- XenForo 2.3+ compatible (tested on XenForo 2.3.7 with PHP 8.3 only)
- Adds one database column to xf_tag table
- Uses XFCP pattern for extensions
- AJAX toggles in admin interface
- Claude Code assisted.

If you spot any issues, please let me know in this thread.