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/forum/index.blade.php

@@ -1,24 +1,16 @@
 @extends('layouts.nova')
 
-@section('content')
-<main class="min-h-screen bg-slate-950 px-4 py-10" aria-labelledby="forum-page-title">
-    <div class="mx-auto max-w-7xl">
-        <header class="mb-8">
-            <h1 id="forum-page-title" class="text-3xl font-semibold text-white">Forum</h1>
-            <p class="mt-2 text-sm text-white/60">Browse forum sections and latest activity.</p>
-        </header>
+@php
+    $forumIndexProps = json_encode([
+        'categories' => $categories ?? [],
+    ], JSON_THROW_ON_ERROR | JSON_UNESCAPED_UNICODE);
+@endphp
 
-        @if (($categories ?? collect())->isEmpty())
-            <div class="rounded-xl border border-white/10 bg-slate-900/60 p-8 text-center text-white/70">
-                No forum categories available yet.
-            </div>
-        @else
-            <div class="grid grid-cols-1 gap-6 md:grid-cols-2 xl:grid-cols-3" role="list" aria-label="Forum categories">
-                @foreach ($categories as $category)
-                    <x-forum.category-card :category="$category" />
-                @endforeach
-            </div>
-        @endif
-    </div>
-</main>
+@section('content')
+<div id="forum-index-root"></div>
+<script type="application/json" id="forum-index-props">{!! $forumIndexProps !!}</script>
 @endsection
+
+@push('scripts')
+    @vite(['resources/js/entry-forum.jsx'])
+@endpush