fix: mark emails back as UNSEEN after FETCH to counter server auto-read

src/email_client.py

@@ -115,18 +115,7 @@ def fetch_unseen_emails(account: EmailAccount) -> list[Email]:
 
     for uid in uids:
         try:
-            _, size_data = conn.uid("FETCH", uid, "(RFC822.SIZE)")
-            size = 0
-            if size_data[0]:
-                m = re.search(rb"RFC822\.SIZE (\d+)", size_data[0])
-                if m:
-                    size = int(m.group(1))
-            large = size > 200_000
-            if large:
-                logger.info("UID %s 大邮件 (%d bytes)，用 PEEK 拉取", uid, size)
-
-            fetch_cmd = "BODY.PEEK[]" if large else "RFC822"
-            _, msg_data = conn.uid("FETCH", uid, fetch_cmd)
+            _, msg_data = conn.uid("FETCH", uid, "RFC822")
             if msg_data[0] is None:
                 logger.warning("UID %s FETCH 返回空，跳过", uid)
                 continue
@@ -144,17 +133,11 @@ def fetch_unseen_emails(account: EmailAccount) -> list[Email]:
             logger.info("  邮件: [%s] from=%s to=%s reply-to=%s (%d 字符)", subject, sender, recipient, reply_to, body_len)
             emails.append(Email(uid=uid, subject=subject, sender=sender, recipient=recipient,
                                 body=body, date=date_str, reply_to=reply_to, account_email=account.username))
+
+            # FETCH 可能被服务器自动标已读，立即标回未读
+            conn.uid("STORE", uid, "-FLAGS", "\\Seen")
         except Exception as e:
-            logger.error("UID %s FETCH 失败，跳过并重建连接: %s", uid, e)
-            try:
-                conn.logout()
-            except Exception:
-                pass
-            try:
-                conn = _login_and_prepare(account)
-            except Exception as e2:
-                logger.error("重建连接失败: %s", e2)
-                break
+            logger.error("UID %s FETCH 失败，跳过: %s", uid, e)
             continue
 
     try: