feat(mindspace): 公开页分享组件、workspace 路径与 Plaza 发布增强

- 新增 public share widget 与 workspace relative path 解析
- 增强 publications/chat-plaza 发布链路与缩略图 demo
- 补充 schema、cover 检查脚本与回归测试

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

src/utils/mindspaceCards.ts

@@ -56,8 +56,8 @@ export function isImageAsset(asset: MindSpaceAsset) {
   return asset.assetType === 'image' || asset.mimeType.startsWith('image/');
 }
 
-export function buildAssetImageUrl(asset: Pick<MindSpaceAsset, 'id' | 'updatedAt' | 'publicUrl'>) {
-  if (asset.publicUrl) return asset.publicUrl;
+export function buildAssetImageUrl(asset: Pick<MindSpaceAsset, 'id' | 'updatedAt'>) {
+  // MindSpace 空间内始终走受鉴权的下载接口，避免 publicUrl（imgproxy / 公开静态路径）在本地或工作区资产上失效。
   return `/api/mindspace/v1/assets/${asset.id}/download?inline=1&viewer=0&v=${asset.updatedAt}`;
 }