fix(creator-studio): 加载正文编辑格式工具栏

选中文字时的 RichText 加粗、斜体、链接等工具由 WordPress format-library 注册。
BlockTools 虽然提供 inline toolbar slot，但此前前台没有加载 wp-format-library，
因此正文选区没有格式工具。为 Creator Studio 前台显式加载该 script/style handle，
并将行内格式工具栏统一为深色圆角悬浮样式。

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

tests/widget-system/creator-studio-contract.test.cjs

@@ -132,6 +132,14 @@ test('studio app keeps autosave, recovery, and the publish drawer wired', () =>
 	assert.match(drawer, /立即发布/);
 });
 
+test('frontend enqueues the WordPress format library for inline RichText tools', () => {
+	const enqueue = read('src/Core/CreatorStudio.php');
+	assert.match(enqueue, /\$deps\[\]\s*=\s*'wp-format-library'/);
+	assert.match(enqueue, /wp-format-library/);
+	assert.match(read('assets/creator-studio/src/index.tsx'), /<BlockTools>/);
+	assert.match(read('assets/creator-studio/src/styles/studio.scss'), /block-editor-rich-text__inline-format-toolbar/);
+});
+
 test('固定顶栏包含保存状态、撤销/重做、预览和发布动作', () => {
 	assert.match(appSource, /className="jio-creator__bar"/);
 	assert.match(appSource, /history\.undo\(\)/);