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

tests/Feature/DashboardFavoritesTest.php

@@ -35,11 +35,9 @@ class DashboardFavoritesTest extends TestCase
 
         $html = $response->getContent();
         $this->assertNotFalse($html);
-        $this->assertStringContainsString('itemprop="thumbnailUrl"', $html);
-        $this->assertStringContainsString('data-blur-preview', $html);
-        $this->assertStringContainsString('loading="lazy"', $html);
-        $this->assertStringContainsString('decoding="async"', $html);
-        $this->assertMatchesRegularExpression('/<img[^>]*data-blur-preview[^>]*/i', $html);
+        $this->assertStringContainsString('data-react-masonry-gallery', $html);
+        $this->assertStringContainsString('data-artworks=', $html);
+        $this->assertStringContainsString('data-gallery-type="dashboard-favorites"', $html);
 
         $this->actingAs($user)
             ->delete(route('dashboard.favorites.destroy', ['artwork' => $art->id]))