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/js/profile.jsx

@@ -0,0 +1,17 @@
+import './bootstrap'
+import React from 'react'
+import { createRoot } from 'react-dom/client'
+import { createInertiaApp } from '@inertiajs/react'
+import ProfileShow from './Pages/Profile/ProfileShow'
+
+const pages = {
+  'Profile/ProfileShow': ProfileShow,
+}
+
+createInertiaApp({
+  resolve: (name) => pages[name],
+  setup({ el, App, props }) {
+    const root = createRoot(el)
+    root.render(<App {...props} />)
+  },
+})