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/Posts/NotificationDigestService.php

@@ -0,0 +1,115 @@
+<?php
+
+namespace App\Services\Posts;
+
+use Illuminate\Database\Eloquent\Collection;
+use Illuminate\Support\Collection as BaseCollection;
+
+/**
+ * Aggregates database notification records into digest groups
+ * so the UI shows "12 people liked your post" instead of 12 separate entries.
+ *
+ * Grouping key: (notifiable_id, data->type, data->post_id, 1-hour bucket)
+ */
+class NotificationDigestService
+{
+    /**
+     * Aggregate a raw notification collection into digest entries.
+     *
+     * @param  \Illuminate\Database\Eloquent\Collection $notifications
+     * @return array<array{
+     *   type: string,
+     *   count: int,
+     *   actors: array,
+     *   post_id: int|null,
+     *   message: string,
+     *   url: string|null,
+     *   latest_at: string,
+     *   read: bool,
+     *   ids: int[],
+     * }>
+     */
+    public function aggregate(Collection $notifications): array
+    {
+        $groups = [];
+
+        foreach ($notifications as $notif) {
+            $data     = is_array($notif->data) ? $notif->data : json_decode($notif->data, true);
+            $type     = $data['type']    ?? 'unknown';
+            $postId   = $data['post_id'] ?? null;
+
+            // 1-hour bucket
+            $bucket = $notif->created_at->format('Y-m-d H');
+
+            $key = "{$type}:{$postId}:{$bucket}";
+
+            if (! isset($groups[$key])) {
+                $groups[$key] = [
+                    'type'      => $type,
+                    'count'     => 0,
+                    'actors'    => [],
+                    'post_id'   => $postId,
+                    'url'       => $data['url'] ?? null,
+                    'latest_at' => $notif->created_at->toISOString(),
+                    'read'      => $notif->read_at !== null,
+                    'ids'       => [],
+                ];
+            }
+
+            $groups[$key]['count']++;
+            $groups[$key]['ids'][] = $notif->id;
+
+            // Collect unique actors (up to 5 for display)
+            $actorId = $data['commenter_id'] ?? $data['reactor_id'] ?? $data['actor_id'] ?? null;
+            if ($actorId && count($groups[$key]['actors']) < 5) {
+                $alreadyAdded = collect($groups[$key]['actors'])->contains('id', $actorId);
+                if (! $alreadyAdded) {
+                    $groups[$key]['actors'][] = [
+                        'id'       => $actorId,
+                        'name'     => $data['commenter_name'] ?? $data['actor_name'] ?? null,
+                        'username' => $data['commenter_username'] ?? $data['actor_username'] ?? null,
+                    ];
+                }
+            }
+
+            if ($notif->read_at === null) {
+                $groups[$key]['read'] = false; // group is unread if any item is unread
+            }
+        }
+
+        // Build readable message for each group
+        $result = [];
+        foreach ($groups as $group) {
+            $group['message'] = $this->buildMessage($group);
+            $result[]         = $group;
+        }
+
+        // Sort by latest_at descending
+        usort($result, fn ($a, $b) => strcmp($b['latest_at'], $a['latest_at']));
+
+        return $result;
+    }
+
+    private function buildMessage(array $group): string
+    {
+        $count   = $group['count'];
+        $actors  = $group['actors'];
+        $first   = $actors[0]['name'] ?? 'Someone';
+        $others  = $count - 1;
+
+        return match ($group['type']) {
+            'post_commented' => $count === 1
+                ? "{$first} commented on your post"
+                : "{$first} and {$others} other(s) commented on your post",
+            'post_liked'     => $count === 1
+                ? "{$first} liked your post"
+                : "{$first} and {$others} other(s) liked your post",
+            'post_shared'    => $count === 1
+                ? "{$first} shared your artwork"
+                : "{$first} and {$others} other(s) shared your artwork",
+            default          => $count === 1
+                ? "{$first} interacted with your post"
+                : "{$count} people interacted with your post",
+        };
+    }
+}