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/NotificationController.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace App\Http\Controllers\Api;
+
+use App\Services\Posts\NotificationDigestService;
+use Illuminate\Http\JsonResponse;
+use Illuminate\Http\Request;
+use App\Http\Controllers\Controller;
+
+/**
+ * GET  /api/notifications           — digestd notification list
+ * POST /api/notifications/read-all  — mark all unread as read
+ * POST /api/notifications/{id}/read — mark single as read
+ */
+class NotificationController extends Controller
+{
+    public function __construct(private NotificationDigestService $digest) {}
+
+    public function index(Request $request): JsonResponse
+    {
+        $user = $request->user();
+        $page = max(1, (int) $request->query('page', 1));
+
+        $notifications = $user->notifications()
+            ->latest()
+            ->limit(200) // aggregate from last 200 raw notifs
+            ->get();
+
+        $digested = $this->digest->aggregate($notifications);
+
+        // Simple manual pagination on the digested array
+        $perPage  = 20;
+        $total    = count($digested);
+        $sliced   = array_slice($digested, ($page - 1) * $perPage, $perPage);
+        $unread   = $user->unreadNotifications()->count();
+
+        return response()->json([
+            'data'         => array_values($sliced),
+            'unread_count' => $unread,
+            'meta'         => [
+                'total'        => $total,
+                'current_page' => $page,
+                'last_page'    => (int) ceil($total / $perPage) ?: 1,
+                'per_page'     => $perPage,
+            ],
+        ]);
+    }
+
+    public function readAll(Request $request): JsonResponse
+    {
+        $request->user()->unreadNotifications->markAsRead();
+        return response()->json(['message' => 'All notifications marked as read.']);
+    }
+
+    public function markRead(Request $request, string $id): JsonResponse
+    {
+        $notif = $request->user()->notifications()->findOrFail($id);
+        $notif->markAsRead();
+        return response()->json(['message' => 'Notification marked as read.']);
+    }
+}