fix: select dropdowns clipped by sections, add approval actions to posts

- Fix CollapsibleSection overflow clipping select dropdowns
- Add SlidePanel footer prop for always-visible save/cancel bar
- Add approval action buttons: Send to Review, Approve, Reject, Schedule
- Add sync-brands.js script for local→remote NocoDB brand sync
- Add posts.reject i18n key (en + ar)

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

client/src/i18n/ar.json

@@ -888,5 +888,6 @@
   "posts.approvers": "المعتمدون",
   "posts.selectApprovers": "اختر المعتمدين...",
   "posts.scheduling": "الجدولة والتعيين",
-  "posts.content": "المحتوى"
+  "posts.content": "المحتوى",
+  "posts.reject": "رفض"
 }