fix(plaza): use hero-generated thumbnails and portal cover URLs

Plaza posts now resolve cover_url to /u/{slug}/pages/{urlSlug}.thumbnail.png
instead of MindSpace workspace paths that fail on plaza.tkmind.cn. Public-html
and chat quick-plaza flows regenerate workspace thumbnails with force:true
after hero images are on disk so feed cards embed the generated art.

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

server/portal-mindspace-chat-share-routes.mjs

@@ -3,6 +3,8 @@ import {
   quickPlazaFromChat,
   quickPlazaFromPublicHtml,
 } from '../mindspace-chat-plaza.mjs';
+import { resolveMindSpaceUserPublishDir } from '../mindspace-runtime-config.mjs';
+import { ensureWorkspaceHtmlThumbnail } from '../mindspace-workspace-thumbnails.mjs';
 
 function assertRouter(api) {
   if (
@@ -41,6 +43,8 @@ export function attachPortalMindSpaceChatShareRoutes(
     getQuickPlazaFromPublicHtmlStatusFn =
       getQuickPlazaFromPublicHtmlStatus,
     quickPlazaFromPublicHtmlFn = quickPlazaFromPublicHtml,
+    ensureWorkspaceHtmlThumbnailFn = ensureWorkspaceHtmlThumbnail,
+    resolveMindSpaceUserPublishDirFn = resolveMindSpaceUserPublishDir,
     now = Date.now,
     logger = console,
   } = {},
@@ -114,6 +118,7 @@ export function attachPortalMindSpaceChatShareRoutes(
         h5Root,
         req.body,
       );
+      const publishDir = resolveMindSpaceUserPublishDirFn(h5Root, req.currentUser);
       const result = await quickPlazaFromChatFn({
         user: req.currentUser,
         bundle,
@@ -121,6 +126,8 @@ export function attachPortalMindSpaceChatShareRoutes(
         mindSpacePages: pages,
         mindSpacePublications: publications,
         plazaPosts,
+        ensureWorkspaceHtmlThumbnail: ensureWorkspaceHtmlThumbnailFn,
+        publishDir,
       });
       logger.info('[quick-plaza] ok', {
         ms: now() - startedAt,
@@ -214,6 +221,7 @@ export function attachPortalMindSpaceChatShareRoutes(
             req.body?.relativePath ??
             '',
         ).trim();
+        const publishDir = resolveMindSpaceUserPublishDirFn(h5Root, req.currentUser);
         const result = await quickPlazaFromPublicHtmlFn({
           user: req.currentUser,
           relativePath,
@@ -222,6 +230,8 @@ export function attachPortalMindSpaceChatShareRoutes(
           plazaPosts,
           readWorkspaceHtml: (input) =>
             chatSave.readWorkspaceHtml(input),
+          ensureWorkspaceHtmlThumbnail: ensureWorkspaceHtmlThumbnailFn,
+          publishDir,
         });
         const plazaUrl = resolvePlazaPostUrl(
           result.post.id,

server/portal-mindspace-chat-share-routes.test.mjs

@@ -1,6 +1,8 @@
 import assert from 'node:assert/strict';
 import test from 'node:test';
 import { attachPortalMindSpaceChatShareRoutes } from './portal-mindspace-chat-share-routes.mjs';
+import { resolveMindSpaceUserPublishDir } from '../mindspace-runtime-config.mjs';
+import { ensureWorkspaceHtmlThumbnail } from '../mindspace-workspace-thumbnails.mjs';
 
 function createRouterRecorder() {
   const routes = new Map();
@@ -194,6 +196,8 @@ test('quick Plaza from chat preserves dependencies, timing, result, and errors',
     mindSpacePages: dependencies.services.pages,
     mindSpacePublications: dependencies.services.publications,
     plazaPosts: dependencies.services.plazaPosts,
+    ensureWorkspaceHtmlThumbnail,
+    publishDir: resolveMindSpaceUserPublishDir('/workspace', req.currentUser),
   });
 
   const failureApi = createRouterRecorder();