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>

mindspace-workspace-path.test.mjs

@@ -0,0 +1,38 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import {
+  resolveAssetWorkspaceRelativePath,
+  resolvePageWorkspaceRelativePath,
+} from './mindspace-workspace-path.mjs';
+
+test('resolvePageWorkspaceRelativePath normalizes html workspace paths', () => {
+  assert.equal(
+    resolvePageWorkspaceRelativePath({ relative_path: 'demo.html' }),
+    'public/demo.html',
+  );
+  assert.equal(resolvePageWorkspaceRelativePath({ relative_path: 'public/demo.html' }), 'public/demo.html');
+  assert.equal(resolvePageWorkspaceRelativePath(null), null);
+});
+
+test('resolveAssetWorkspaceRelativePath prefers explicit public image paths', () => {
+  assert.equal(
+    resolveAssetWorkspaceRelativePath({
+      explicitPath: 'public/images/2026-07-05/hero.png',
+    }),
+    'public/images/2026-07-05/hero.png',
+  );
+  assert.equal(
+    resolveAssetWorkspaceRelativePath({
+      categoryCode: 'public',
+      originalFilename: 'report.docx',
+    }),
+    'public/report.docx',
+  );
+  assert.equal(
+    resolveAssetWorkspaceRelativePath({
+      categoryCode: 'draft',
+      originalFilename: 'notes.md',
+    }),
+    null,
+  );
+});