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

app/Http/Controllers/Api/Posts/PostFeedController.php

@@ -0,0 +1,60 @@
+<?php
+
+namespace App\Http\Controllers\Api\Posts;
+
+use App\Http\Controllers\Controller;
+use App\Models\User;
+use App\Services\Posts\PostFeedService;
+use Illuminate\Http\JsonResponse;
+use Illuminate\Http\Request;
+
+class PostFeedController extends Controller
+{
+    public function __construct(private PostFeedService $feedService) {}
+
+    // ─────────────────────────────────────────────────────────────────────────
+    // Profile feed — GET /api/posts/profile/{username}
+    // ─────────────────────────────────────────────────────────────────────────
+
+    public function profile(Request $request, string $username): JsonResponse
+    {
+        $profileUser = User::where('username', $username)->firstOrFail();
+        $viewerId    = $request->user()?->id;
+        $page        = max(1, (int) $request->query('page', 1));
+
+        $paginated = $this->feedService->getProfileFeed($profileUser, $viewerId, $page);
+
+        $formatted = collect($paginated['data'])
+            ->map(fn ($post) => $this->feedService->formatPost($post, $viewerId))
+            ->values();
+
+        return response()->json([
+            'data' => $formatted,
+            'meta' => $paginated['meta'],
+        ]);
+    }
+
+    // ─────────────────────────────────────────────────────────────────────────
+    // Following feed — GET /api/posts/following
+    // ─────────────────────────────────────────────────────────────────────────
+
+    public function following(Request $request): JsonResponse
+    {
+        $user   = $request->user();
+        $page   = max(1, (int) $request->query('page', 1));
+        $filter = $request->query('filter', 'all');
+
+        $result = $this->feedService->getFollowingFeed($user, $page, $filter);
+
+        $viewerId  = $user->id;
+        $formatted = array_map(
+            fn ($post) => $this->feedService->formatPost($post, $viewerId),
+            $result['data'],
+        );
+
+        return response()->json([
+            'data' => $formatted,
+            'meta' => $result['meta'],
+        ]);
+    }
+}