fix(brand): require TKMind platform marker on wechat page delivery

Backfill missing platform-brand footer at serve time and block service-
account links when the HTML file omits data-mindspace-page-tag.

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

wechat/prompts/page-generate.mjs

@@ -28,7 +28,7 @@ export function buildPageGenerateAgentPrompt(intent, { wantsDocx = false } = {})
     '   - `<meta name="description" content="一句话摘要">`',
     '   - `<meta name="mindspace-cover" content=\'{"tag":"主题","accent":"#主色","accent2":"#辅色","subtitle":"卖点","cover":"assets/hero.jpg"}\'>`',
     '   tag/accent/subtitle 必须与页面主题一致；有 hero 图时 cover 指向同目录 raster 图（jpg/png）。',
-    '6. 页脚加 `<footer data-mindspace-page-tag="platform-brand">` 以显示 TKMind 智趣 品牌。',
+    '6. 页脚加 `<p data-mindspace-page-tag="platform-brand">TKMind · 智趣</p>`（必须，禁止省略或用邮箱/tkmind.ai 代替）。',
     '7. 回复里只给一个正式域名链接；没有落盘或缺少上述元数据就不要发链接。',
     '',
     buildCurrentTimeAgentPrefix({ timezone: scheduleTimezone }),
@@ -38,7 +38,13 @@ export function buildPageGenerateAgentPrompt(intent, { wantsDocx = false } = {})
     .join('\n');
 }
 
-export function buildPagePublishFailureText({ missingSharePreview = false } = {}) {
+export function buildPagePublishFailureText({ missingSharePreview = false, missingPlatformBrand = false } = {}) {
+  if (missingPlatformBrand) {
+    return [
+      '这次页面已落盘，但缺少页脚平台品牌标记（data-mindspace-page-tag="platform-brand"），所以我先不发链接。',
+      '请直接重发一次完整页面需求，我会重新按 static-page-publish 技能生成带 TKMind · 智趣 品牌页脚的页面。',
+    ].join('\n');
+  }
   if (missingSharePreview) {
     return [
       '这次页面已落盘，但缺少微信分享卡片所需的预览元数据（mindspace-cover 与摘要），所以我先不发链接。',