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-page-sync.mjs

@@ -33,13 +33,19 @@ async function findPageByWorkspaceRelativePath(pool, userId, relativePath) {
   const [rows] = await pool.query(
     `SELECT p.id, p.updated_at
      FROM h5_page_records p
-     JOIN h5_page_versions pv ON pv.id = p.current_version_id
+     LEFT JOIN h5_page_versions pv ON pv.id = p.current_version_id
      WHERE p.user_id = ?
        AND p.status <> 'deleted'
-       AND JSON_UNQUOTE(JSON_EXTRACT(pv.source_snapshot_json, '$.relative_path')) = ?
+       AND (
+         p.workspace_relative_path = ?
+         OR (
+           (p.workspace_relative_path IS NULL OR p.workspace_relative_path = '')
+           AND JSON_UNQUOTE(JSON_EXTRACT(pv.source_snapshot_json, '$.relative_path')) = ?
+         )
+       )
      ORDER BY p.updated_at DESC, p.id DESC
      LIMIT 1`,
-    [userId, relativePath],
+    [userId, relativePath, relativePath],
   );
   const row = rows[0];
   if (!row) return null;
@@ -58,16 +64,18 @@ function parseJsonColumn(value, fallback = {}) {
 
 async function loadIndexedWorkspacePages(pool, userId) {
   const [rows] = await pool.query(
-    `SELECT p.id, p.updated_at, p.source_asset_id, pv.source_snapshot_json
+    `SELECT p.id, p.updated_at, p.source_asset_id, p.workspace_relative_path, pv.source_snapshot_json
      FROM h5_page_records p
-     JOIN h5_page_versions pv ON pv.id = p.current_version_id
+     LEFT JOIN h5_page_versions pv ON pv.id = p.current_version_id
      WHERE p.user_id = ? AND p.status <> 'deleted'`,
     [userId],
   );
   const byPath = new Map();
   for (const row of rows) {
     const snapshot = parseJsonColumn(row.source_snapshot_json);
-    const relativePath = normalizePublicHtmlPath(snapshot.relative_path);
+    const relativePath =
+      normalizePublicHtmlPath(row.workspace_relative_path) ??
+      normalizePublicHtmlPath(snapshot.relative_path);
     if (relativePath) {
       byPath.set(relativePath, {
         id: row.id,