chore: baseline snapshot before moderation-strictness feature

Repo .git was damaged (refs/ missing, index truncated, object store near-empty).
Repaired via git init (rebuilt refs), stale index preserved as .git/index.corrupt-20260910.bak,
then full worktree committed as a rollback baseline.

templates/mail/new-conversation.html

@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html>
+<head><meta charset="UTF-8"></head>
+<body>
+  <p>您好！</p>
+  <p>您收到一个新的私聊对话，内容如下：</p>
+  <div style="border-left: 4px solid #e0e0e0; padding: 12px; margin: 12px 0; background-color: #f9f9f9; border-radius: 4px; color: #333333;">
+    {{.content}}
+  </div>
+  <p>点击下方链接查看并回复：</p>
+  <p><a href="{{.link}}">{{.link}}</a></p>
+  <br>
+  <p style="color: #999999; font-size: 12px;">此邮件由系统自动发送，请勿回复。<br>© {{.year}} 狼的提问箱</p>
+</body>
+</html>