Add Tiptap enhancements and webinar date/time fields

- Add text alignment controls to Tiptap editor (left, center, right, justify)
- Add horizontal rule/spacer button to Tiptap toolbar
- Add event_start and duration_minutes fields to webinar products
- Add webinar status badges (Recording Available, Coming Soon, Ended)
- Install @tiptap/extension-text-align package

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

package.json

@@ -48,6 +48,7 @@
     "@tiptap/extension-table-cell": "^3.14.0",
     "@tiptap/extension-table-header": "^3.14.0",
     "@tiptap/extension-table-row": "^3.14.0",
+    "@tiptap/extension-text-align": "^3.14.0",
     "@tiptap/react": "^3.13.0",
     "@tiptap/starter-kit": "^3.13.0",
     "class-variance-authority": "^0.7.1",