feat: use xpier media library for uploads and markdown embeds

Store media:ID in post bodies instead of CDN URLs, and keep sablog attach tokens as a fallback.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/Models/Post.php

@@ -11,6 +11,7 @@ use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Illuminate\Database\Eloquent\Relations\HasMany;
 use Spatie\MediaLibrary\HasMedia;
+use Xpier\FilamentMediaLibrary\Models\MediaLibrary;
 use Spatie\MediaLibrary\InteractsWithMedia;
 use Spatie\MediaLibrary\MediaCollections\Models\Media;
 use Spatie\Tags\HasTags;
@@ -30,6 +31,7 @@ class Post extends Model implements HasMedia
         'content',
         'content_format',
         'keywords',
+        'cover_media_id',
         'status',
         'is_sticky',
         'close_comment',
@@ -57,6 +59,26 @@ class Post extends Model implements HasMedia
         return $this->belongsTo(User::class, 'user_id');
     }
 
+    public function coverMedia(): BelongsTo
+    {
+        return $this->belongsTo(MediaLibrary::class, 'cover_media_id');
+    }
+
+    public function coverImageUrl(?string $conversion = 'card'): ?string
+    {
+        $libraryUrl = $this->coverMedia?->url;
+        if (filled($libraryUrl)) {
+            return (string) $libraryUrl;
+        }
+
+        $cover = $this->getFirstMedia('cover');
+        if ($cover === null) {
+            return null;
+        }
+
+        return $cover->getUrl($conversion) ?: $cover->getUrl();
+    }
+
     public function comments(): HasMany
     {
         return $this->hasMany(Comment::class);
@@ -133,8 +155,10 @@ class Post extends Model implements HasMedia
 
         $text = strip_tags($this->content);
         // 付费块不进入摘要，避免付费内容泄漏到列表页/SEO meta
-        $text = preg_replace('/\[paid\].*?\[\/paid\]/s', '', $text);
-        $text = preg_replace('/\[[^\]]*\]/', '', $text);
+        $text = preg_replace('/\[paid\].*?\[\/paid\]/s', '', $text) ?? $text;
+        $text = preg_replace('/!\[([^\]]*)\]\((?:media|attach):\d+\)/i', '$1', $text) ?? $text;
+        $text = preg_replace('/\[([^\]]*)\]\((?:media|attach):\d+\)/i', '$1', $text) ?? $text;
+        $text = preg_replace('/\[[^\]]*\]/', '', $text) ?? $text;
 
         return mb_substr($text, 0, 200);
     }