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/views/web/discover/index.blade.php

@@ -17,34 +17,7 @@
         </div>
 
         {{-- Section switcher pills --}}
-        <div class="flex flex-wrap items-center gap-2 text-sm">
-            @auth
-            <a href="{{ route('discover.for-you') }}"
-               class="inline-flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm font-medium transition-colors bg-white/[0.05] text-white/60 hover:bg-white/[0.1] hover:text-white">
-                <i class="fa-solid fa-wand-magic-sparkles text-xs text-yellow-400/80"></i>
-                For You
-            </a>
-            @endauth
-            @php
-                $sections = [
-                    'trending'        => ['label' => 'Trending',        'icon' => 'fa-fire'],
-                    'rising'          => ['label' => 'Rising',          'icon' => 'fa-rocket'],
-                    'fresh'           => ['label' => 'Fresh',           'icon' => 'fa-bolt'],
-                    'top-rated'       => ['label' => 'Top Rated',       'icon' => 'fa-medal'],
-                    'most-downloaded' => ['label' => 'Most Downloaded', 'icon' => 'fa-download'],
-                    'on-this-day'     => ['label' => 'On This Day',     'icon' => 'fa-calendar-day'],
-                ];
-                $active = $section ?? '';
-            @endphp
-            @foreach($sections as $slug => $meta)
-                <a href="{{ route('discover.' . $slug) }}"
-                   class="inline-flex items-center gap-1.5 px-3 py-1.5 rounded-lg text-sm font-medium transition-colors
-                          {{ $active === $slug ? 'bg-sky-600 text-white' : 'bg-white/[0.05] text-white/60 hover:bg-white/[0.1] hover:text-white' }}">
-                    <i class="fa-solid {{ $meta['icon'] }} text-xs"></i>
-                    {{ $meta['label'] }}
-                </a>
-            @endforeach
-        </div>
+        @include('web.discover._nav', ['section' => $section ?? ''])
     </div>
 </div>