修复作品架已发布卡片分享入口

为作品架分享按钮补充可见底色与回归测试
将已发布作品卡分享动作接入统一发布分享弹窗
同步玩法链路文档中的作品架分享口径

src/index.test.ts

@@ -103,6 +103,17 @@ describe('index stylesheet unread dots', () => {
       expect(block).not.toContain('rgba(239, 68, 68');
     }
   });
+
+  it('keeps the creation shelf share button on a visible surface', () => {
+    const css = readIndexCss();
+    const block = getCssBlock(css, '.creation-work-card__quick-action-button');
+
+    expect(block).toContain('border: 1px solid');
+    expect(block).toContain('background: color-mix(');
+    expect(block).toContain('var(--platform-neutral-bg)');
+    expect(block).toContain('var(--platform-cool-bg)');
+    expect(block).not.toContain('background: transparent;');
+  });
 });
 
 describe('index stylesheet draft mobile cards', () => {