feat(creator-studio): switch writing editor to TinyMCE

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

assets/creator-studio/scripts/preview.cjs

@@ -21,7 +21,7 @@ const mockBootstrap = {
   title: '',
   excerpt: '',
   content:
-    '<!-- wp:paragraph --><p>这是正文的第一段。微信公众号式的编辑体验强调沉浸感：大面积留白、克制的工具栏、只在需要时才出现的设置面板。</p><!-- /wp:paragraph -->',
+    '<p>这是正文的第一段。微信公众号式的编辑体验强调沉浸感：留白克制，固定工具栏始终可用，发布设置只在需要时打开。</p>',
   permalink: '',
   isPublished: false,
   categories: {
@@ -81,7 +81,6 @@ const mockBootstrap = {
     privateUrl: '#',
     bootstrapUrl: '#',
   },
-  blocks: { mediaUploadUrl: '#', mediaListUrl: '#' },
   nonce: 'preview',
 };