fix(mindspace): edit_file 落盘、Finish 聊天 merge 与回归守卫

- finish-sync 支持 edit_file 覆盖 public HTML
- Finish 同步 merge 本地流式消息，剥离 agent 内部前缀
- 新增 verify:mindspace-publish-guards 与 AGENTS.md 跨工具说明
- 发版脚本接入回归门禁；103 runtime 发布含备份回退

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

session-snapshot.mjs

@@ -11,6 +11,8 @@
  * conversation content, so it can be dropped/truncated safely at any time.
  */
 
+import { deriveUserFacingText } from './conversation-display.mjs';
+
 const DERIVED_TITLE_MAX_LEN = 40;
 
 function isGeneratedSessionName(name) {
@@ -29,6 +31,9 @@ function messageSnippet(message) {
     .map((item) => item.text)
     .join('')
     .trim();
+  if (message?.role === 'user') {
+    return deriveUserFacingText(fromContent);
+  }
   if (fromContent) return fromContent;
   const displayText = message?.metadata?.displayText;
   return typeof displayText === 'string' ? displayText.trim() : '';