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/Services/Uploads/UploadStorageService.php

@@ -76,33 +76,6 @@ final class UploadStorageService
         return $dir;
     }
 
-    public function publicHashDirectory(string $hash): string
-    {
-        $prefix = trim((string) config('uploads.public_img_prefix', 'img'), DIRECTORY_SEPARATOR);
-        $base = $this->sectionPath('public') . DIRECTORY_SEPARATOR . $prefix;
-
-        if (! File::exists($base)) {
-            File::makeDirectory($base, 0755, true);
-        }
-
-        $segments = $this->hashSegments($hash);
-        $dir = $base . DIRECTORY_SEPARATOR . implode(DIRECTORY_SEPARATOR, $segments);
-
-        if (! File::exists($dir)) {
-            File::makeDirectory($dir, 0755, true);
-        }
-
-        return $dir;
-    }
-
-    public function publicRelativePath(string $hash, string $filename): string
-    {
-        $prefix = trim((string) config('uploads.public_img_prefix', 'img'), DIRECTORY_SEPARATOR);
-        $segments = $this->hashSegments($hash);
-
-        return $prefix . '/' . implode('/', $segments) . '/' . ltrim($filename, '/');
-    }
-
     public function sectionRelativePath(string $section, string $hash, string $filename): string
     {
         $segments = $this->hashSegments($hash);
@@ -111,6 +84,24 @@ final class UploadStorageService
         return $section . '/' . implode('/', $segments) . '/' . ltrim($filename, '/');
     }
 
+    public function originalHashExists(string $hash): bool
+    {
+        $segments = $this->hashSegments($hash);
+        $dir = $this->sectionPath('original') . DIRECTORY_SEPARATOR . implode(DIRECTORY_SEPARATOR, $segments);
+
+        if (! File::isDirectory($dir)) {
+            return false;
+        }
+
+        $normalizedHash = strtolower(preg_replace('/[^a-z0-9]/', '', $hash) ?? '');
+        if ($normalizedHash === '') {
+            return false;
+        }
+
+        $matches = File::glob($dir . DIRECTORY_SEPARATOR . $normalizedHash . '.*');
+        return is_array($matches) && count($matches) > 0;
+    }
+
     private function safeExtension(UploadedFile $file): string
     {
         $extension = (string) $file->guessExtension();
@@ -125,10 +116,11 @@ final class UploadStorageService
         $hash = preg_replace('/[^a-z0-9]/', '', $hash) ?? '';
         $hash = str_pad($hash, 6, '0');
 
+        // Use two 2-char segments for directory sharding: first two chars, next two chars.
+        // Result: <section>/<aa>/<bb>/<filename>
         $segments = [
             substr($hash, 0, 2),
             substr($hash, 2, 2),
-            substr($hash, 4, 2),
         ];
 
         return array_map(static fn (string $part): string => $part === '' ? '00' : $part, $segments);