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>

scripts/mindspace-publications-e2e.mjs

@@ -198,6 +198,29 @@ try {
   assert.match(stillV1.body, /V1 内容/);
   assert.doesNotMatch(stillV1.body, /V2 内容/);
 
+  const blockedRepublish = await request(`/api/mindspace/v1/pages/${page.id}/publish`, {
+    method: 'POST',
+    headers: authHeaders(owner.cookie),
+    body: JSON.stringify({
+      page_version_id: updated.body.data.currentVersionId,
+      access_mode: 'owner_only',
+      url_slug: 'immutable-page',
+      acknowledged_finding_ids: [],
+    }),
+  });
+  assert.equal(blockedRepublish.response.status, 409);
+  assert.equal(blockedRepublish.body.error.code, 'page_already_online');
+
+  const offlineBeforeRepublish = await request(
+    `/api/mindspace/v1/publications/${published.body.data.id}/offline`,
+    {
+      method: 'POST',
+      headers: authHeaders(owner.cookie),
+      body: '{}',
+    },
+  );
+  assert.equal(offlineBeforeRepublish.response.status, 200);
+
   const republished = await request(`/api/mindspace/v1/pages/${page.id}/publish`, {
     method: 'POST',
     headers: authHeaders(owner.cookie),
@@ -218,7 +241,21 @@ try {
   assert.equal(ownerProtected.response.status, 200);
   assert.match(ownerProtected.body, /V2 内容/);
 
+  let currentPublicationId = republished.body.data.id;
+  const offlineCurrentPublication = async () => {
+    const response = await request(
+      `/api/mindspace/v1/publications/${currentPublicationId}/offline`,
+      {
+        method: 'POST',
+        headers: authHeaders(owner.cookie),
+        body: '{}',
+      },
+    );
+    assert.equal(response.response.status, 200, JSON.stringify(response.body));
+  };
+
   const publishMode = async (accessMode, extra = {}) => {
+    await offlineCurrentPublication();
     const response = await request(`/api/mindspace/v1/pages/${page.id}/publish`, {
       method: 'POST',
       headers: authHeaders(owner.cookie),
@@ -231,6 +268,7 @@ try {
       }),
     });
     assert.equal(response.response.status, 201, JSON.stringify(response.body));
+    currentPublicationId = response.body.data.id;
     return response.body.data;
   };