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/components/Feed/VisibilityPill.jsx

@@ -0,0 +1,22 @@
+import React from 'react'
+
+const ICONS = {
+  public:    { icon: 'fa-globe',        label: 'Public',    cls: 'text-slate-500' },
+  followers: { icon: 'fa-user-friends', label: 'Followers', cls: 'text-sky-500/70' },
+  private:   { icon: 'fa-lock',         label: 'Private',   cls: 'text-amber-500/70' },
+}
+
+export default function VisibilityPill({ visibility, showLabel = false }) {
+  const v = ICONS[visibility] ?? ICONS.public
+
+  return (
+    <span
+      className={`inline-flex items-center gap-1 text-xs ${v.cls}`}
+      title={v.label}
+      aria-label={`Visibility: ${v.label}`}
+    >
+      <i className={`fa-solid ${v.icon} fa-fw`} />
+      {showLabel && <span>{v.label}</span>}
+    </span>
+  )
+}