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/PostController.php

@@ -0,0 +1,92 @@
+<?php
+
+namespace App\Http\Controllers\Api\Posts;
+
+use App\Http\Controllers\Controller;
+use App\Http\Requests\Posts\CreatePostRequest;
+use App\Http\Requests\Posts\UpdatePostRequest;
+use App\Models\Post;
+use App\Services\Posts\PostFeedService;
+use App\Services\Posts\PostService;
+use Carbon\Carbon;
+use Illuminate\Http\JsonResponse;
+use Illuminate\Support\Facades\Gate;
+use Illuminate\Support\Facades\RateLimiter;
+
+class PostController extends Controller
+{
+    public function __construct(
+        private PostService     $postService,
+        private PostFeedService $feedService,
+    ) {}
+
+    // ─────────────────────────────────────────────────────────────────────────
+    // Create
+    // ─────────────────────────────────────────────────────────────────────────
+
+    public function store(CreatePostRequest $request): JsonResponse
+    {
+        $user = $request->user();
+
+        // Rate limit: 10 post creations per hour
+        $key = 'create_post:' . $user->id;
+        if (RateLimiter::tooManyAttempts($key, 10)) {
+            $seconds = RateLimiter::availableIn($key);
+            return response()->json([
+                'message' => "You're posting too quickly. Please wait {$seconds} seconds.",
+            ], 429);
+        }
+        RateLimiter::hit($key, 3600);
+
+        Gate::authorize('create', Post::class);
+
+        $post = $this->postService->createPost(
+            user:         $user,
+            type:         $request->input('type', Post::TYPE_TEXT),
+            visibility:   $request->input('visibility', Post::VISIBILITY_PUBLIC),
+            body:         $request->input('body'),
+            targets:      $request->input('targets', []),
+            linkPreview:  $request->input('link_preview'),
+            taggedUsers:  $request->input('tagged_users'),            publishAt:   $request->filled('publish_at') ? Carbon::parse($request->input('publish_at')) : null,        );
+
+        $post->load(['user', 'user.profile', 'targets', 'targets.artwork', 'targets.artwork.user', 'targets.artwork.user.profile', 'reactions']);
+
+        return response()->json([
+            'post' => $this->feedService->formatPost($post, $user->id),
+        ], 201);
+    }
+
+    // ─────────────────────────────────────────────────────────────────────────
+    // Update
+    // ─────────────────────────────────────────────────────────────────────────
+
+    public function update(UpdatePostRequest $request, int $id): JsonResponse
+    {
+        $post = Post::findOrFail($id);
+        Gate::authorize('update', $post);
+
+        $updated = $this->postService->updatePost(
+            post:       $post,
+            body:       $request->input('body'),
+            visibility: $request->input('visibility'),
+        );
+
+        return response()->json([
+            'post' => $this->feedService->formatPost($updated->load(['user', 'user.profile', 'targets', 'targets.artwork', 'targets.artwork.user', 'targets.artwork.user.profile', 'reactions']), $request->user()?->id),
+        ]);
+    }
+
+    // ─────────────────────────────────────────────────────────────────────────
+    // Delete
+    // ─────────────────────────────────────────────────────────────────────────
+
+    public function destroy(int $id): JsonResponse
+    {
+        $post = Post::findOrFail($id);
+        Gate::authorize('delete', $post);
+
+        $this->postService->deletePost($post);
+
+        return response()->json(['message' => 'Post deleted.']);
+    }
+}