Add contact form inbox to admin portal; v2.0.25

- New Inbox view in the Audience nav group shows all contact form submissions
- Filter by Unread / All / Archived with a search bar for name, email, or message
- Click any message to open a detail pane with full text, metadata, and a Reply via Email link
- Archive / Unarchive button to clear messages without deleting them
- Unread badge on the Inbox nav item; dashboard card now links directly to Inbox
- Added PATCH /api/admin-contact-submissions/:id to persist archived state

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package.json

@@ -1,7 +1,7 @@
 {
   "name": "siteforge",
   "private": true,
-  "version": "2.0.24",
+  "version": "2.0.25",
   "type": "module",
   "scripts": {
     "dev": "vite",