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/EmbeddedArtworkCard.jsx

@@ -0,0 +1,54 @@
+import React from 'react'
+
+/**
+ * Compact artwork card for embedding inside a PostCard.
+ * Shows thumbnail, title and original author with attribution.
+ */
+export default function EmbeddedArtworkCard({ artwork }) {
+  if (!artwork) return null
+
+  const artUrl    = `/art/${artwork.id}/${slugify(artwork.title)}`
+  const authorUrl = `/@${artwork.author.username}`
+
+  return (
+    <a
+      href={artUrl}
+      className="group flex gap-3 rounded-xl border border-white/[0.08] bg-black/30 p-3 hover:border-sky-500/30 transition-colors"
+      title={artwork.title}
+    >
+      {/* Thumbnail */}
+      <div className="w-20 h-16 rounded-lg overflow-hidden shrink-0 bg-white/5">
+        {artwork.thumb_url ? (
+          <img
+            src={artwork.thumb_url}
+            alt={artwork.title}
+            className="w-full h-full object-cover transition-transform duration-300 group-hover:scale-105"
+            loading="lazy"
+          />
+        ) : (
+          <div className="w-full h-full flex items-center justify-center text-slate-600">
+            <i className="fa-solid fa-image" />
+          </div>
+        )}
+      </div>
+
+      {/* Meta */}
+      <div className="flex flex-col justify-center min-w-0">
+        <p className="text-sm font-medium text-white/90 truncate">{artwork.title}</p>
+        <a
+          href={authorUrl}
+          onClick={(e) => e.stopPropagation()}
+          className="text-xs text-slate-400 hover:text-sky-400 transition-colors mt-0.5 truncate"
+        >
+          <i className="fa-solid fa-user-circle fa-fw mr-1 opacity-60" />
+          by {artwork.author.name || `@${artwork.author.username}`}
+        </a>
+        <span className="text-[10px] text-slate-600 mt-1 uppercase tracking-wider">Artwork</span>
+      </div>
+    </a>
+  )
+}
+
+function slugify(str) {
+  return (str || '').toLowerCase().replace(/[^a-z0-9]+/g, '-').replace(/^-|-$/g, '')
+}