fix(wechat): repair share preview on disk for sanitized delivery artifacts

Production WeChat delivery strips localPath from artifacts, so share-preview
auto-repair never wrote back to HTML. Resolve paths via publishDir +
relativePath, repair at materialize and delivery prep, and pass h5Root from
Portal so page.generate can patch missing meta before sending links.

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

mindspace-wechat-html-delivery.mjs

@@ -17,6 +17,9 @@ import {
 import {
   verifySharePreviewMeta,
 } from './wechat/verify/share-preview.mjs';
+import {
+  ensureArtifactsSharePreviewReady,
+} from './wechat/verify/share-preview-repair.mjs';
 
 const PUBLIC_HTML_LINK_PATTERN =
   /https?:\/\/[^\s<>"')\]]+\/MindSpace\/([0-9a-f-]{36}|[a-z0-9._-]+)\/public\/([^\s<>"')\]]+\.html)/gi;
@@ -397,11 +400,26 @@ export function prepareWechatHtmlDeliveryAtWorkspace({
         requestStartedAt,
       })
     : [];
-  const confirmedArtifacts = uniqueArtifacts([
-    ...publishedArtifacts,
-    ...expectedArtifacts,
-    ...recentArtifacts,
-  ]);
+  const confirmedArtifacts = ensureArtifactsSharePreviewReady(
+    uniqueArtifacts([
+      ...publishedArtifacts,
+      ...expectedArtifacts,
+      ...recentArtifacts,
+    ]),
+    {
+      publishDir,
+      topic: String(
+        intent?.agentText ?? intent?.displayText ?? '',
+      ).trim(),
+    },
+  ).map(
+    (artifact) =>
+      readArtifactDescriptor(artifact.relativePath, {
+        publishDir,
+        buildCanonicalUrl,
+        copyIntoPublic: false,
+      }) ?? artifact,
+  );
   const linkedFilenames =
     collectLinkedHtmlFilenames(reply?.text);
   const matchedArtifacts =
@@ -610,6 +628,7 @@ export async function ensureWechatFreshPageThumbnailsAtWorkspace({
     verifyFreshWechatPageThumbnails(
       workspaceArtifacts,
       images,
+      { publishDir },
     );
   let repair = null;
   if (
@@ -638,6 +657,7 @@ export async function ensureWechatFreshPageThumbnailsAtWorkspace({
         verifyFreshWechatPageThumbnails(
           workspaceArtifacts,
           images,
+          { publishDir },
         );
     }
   }