feat: forum rich-text editor, emoji picker, mentions, discover nav, feed, uploads, profile

Forum:
- TipTap WYSIWYG editor with full toolbar
- @emoji-mart/react emoji picker (consistent with tweets)
- @mention autocomplete with user search API
- Fix PHP 8.4 parse errors in Blade templates
- Fix thread data display (paginator items)
- Align forum page widths to max-w-5xl

Discover:
- Extract shared _nav.blade.php partial
- Add missing nav links to for-you page
- Add Following link for authenticated users

Feed/Posts:
- Post model, controllers, policies, migrations
- Feed page components (PostComposer, FeedCard, etc)
- Post reactions, comments, saves, reports, sharing
- Scheduled publishing support
- Link preview controller

Profile:
- Profile page components (ProfileHero, ProfileTabs)
- Profile API controller

Uploads:
- Upload wizard enhancements
- Scheduled publish picker
- Studio status bar and readiness checklist

resources/js/components/ui/NovaSelect.jsx

@@ -77,9 +77,13 @@ export default function NovaSelect({
     const dropH = Math.min(280, filtered.length * 38 + 52) // approx
     const openUp = spaceBelow < dropH + 8 && spaceAbove > spaceBelow
 
+    // Clamp horizontal position so the dropdown doesn't render off-screen or far away
+    const padding = 8
+    const leftClamped = Math.max(padding, Math.min(rect.left, window.innerWidth - rect.width - padding))
+
     setDropPos({
       top:   openUp ? rect.top - dropH - 4 : rect.bottom + 4,
-      left:  rect.left,
+      left:  leftClamped,
       width: rect.width,
       openUp,
     })