fix(unsub): List-Unsubscribe 头兜底 + mailto 退订按钮放行

两封推广邮件无退订按钮，两个独立根因：
1. Cloudflare 邮件 (msg_id=1364)：程序只喂纯文本给 AI，纯文本里
   'Unsubscribe' 无 URL；邮件头 List-Unsubscribe 的权威退订链接被丢弃。
   -> 解析 List-Unsubscribe 头 (RFC 2369) 存入 Email.list_unsubscribe，
      注入 AI 提示词；显示层新增 _ensure_unsub_link 兜底：AI 漏提取时
      直接用头部 http(s)/mailto 链接补退订按钮（不依赖 AI）。
2. InferX 邮件 (msg_id=1363)：AI 提取到 mailto:team@inferx.net?subject=Unsubscribe，
   但 _link_buttons 只放行 http 协议把它过滤掉。
   -> URL 校验放行 mailto:（退订场景常见）。

send_summary / tg_send_and_mark 均应用兜底并写回 summary_data.links，
回调恢复视图也能显示退订按钮。新增 6 个测试，共 14 个全部通过。

src/ai_client.py

@@ -31,6 +31,7 @@ SYSTEM_PROMPT = """你是一个邮件摘要助手。请分析邮件内容并以
 - app_name: 仅当 category 为 "notification" 且邮件包含验证码时填写，填写发送验证码的应用/平台名称（如「GitHub」「微信」「Kraken」）。非验证码邮件留空字符串
 - links: 提取用户需要点击的链接。其中退订/取消订阅链接按下方「退订链接提取规则」强制执行，其余仅提取邮件明确要求用户点击才能完成某操作的链接（如确认邮箱、重置密码、查看账单、审批请求、查看通知详情等）。不要提取推广性质的链接（如下载App、注册领优惠、查看更多商品等营销链接）、追踪像素、邮件签名中的社交链接。每条包含简短描述文字和完整 URL。最多 3 条。没有符合条件的链接时为空数组
 - 退订链接提取规则（最高优先级，仅适用于 category 为 "promotion" 的邮件）：
+  * 若邮件头提供了 List-Unsubscribe 头（用户消息中「List-Unsubscribe:」行），该链接是权威退订入口，优先使用它作为退订链接（除非它明显是 mailto: 形式而正文里能找到更好的 http 链接，此时两者取其一即可）
   * 推广邮件必须在 links 中输出退订链接，且放在 links 数组的第一位；只有邮件正文确实不存在任何退订入口时，links 才可以为空
   * 退订链接通常位于邮件最底部/页脚区域，表现形式多样：文字为 unsubscribe、Unsubscribe、退订、取消订阅、点击这里退订、manage preferences、email preferences、update preferences、subscription settings、opt out 等；也可能是图片链接，或包裹在 HTML 标签中的 <a href="...">，必须提取 href 属性里的完整 URL
   * 同一封邮件出现多个退订相关链接时，只提取最主要的那个（优先取正文最后出现的完整 unsubscribe 链接）
@@ -44,10 +45,13 @@ SYSTEM_PROMPT = """你是一个邮件摘要助手。请分析邮件内容并以
 
 
 @retry()
-def summarize_email(ai_cfg: AIConfig, recipient: str, subject: str, sender: str, body: str, account: str = "") -> dict[str, Any]:
+def summarize_email(ai_cfg: AIConfig, recipient: str, subject: str, sender: str, body: str,
+                    account: str = "", list_unsubscribe: str = "") -> dict[str, Any]:
     body_preview = body[:80].replace("\n", " ")
     logger.info("AI 摘要请求: sender=%s subject=%s body_preview=%s", sender, subject, body_preview)
     content = f"收件人: {recipient}\n发件人: {sender}\n主题: {subject}\n账号: {account}\n正文:\n{body}"
+    if list_unsubscribe:
+        content += f"\n\nList-Unsubscribe: {list_unsubscribe}"
 
     payload = {
         "model": ai_cfg.model,

src/email_client.py

@@ -14,7 +14,7 @@ logger = logging.getLogger(__name__)
 class Email:
     def __init__(self, uid: bytes, subject: str, sender: str, recipient: str,
                  body: str, date: str, reply_to: str = "", account_email: str = "",
-                 folder: str = "INBOX", cc: str = ""):
+                 folder: str = "INBOX", cc: str = "", list_unsubscribe: str = ""):
         self.uid = uid
         self.subject = subject
         self.sender = sender
@@ -25,6 +25,7 @@ class Email:
         self.account_email = account_email
         self.folder = folder
         self.cc = cc
+        self.list_unsubscribe = list_unsubscribe
 
 
 def _decode_str(s: str) -> str:
@@ -72,6 +73,31 @@ def _get_text_from_msg(msg) -> str:
     return ""
 
 
+def _parse_list_unsubscribe(header_value: str) -> str:
+    """解析 List-Unsubscribe 头（RFC 2369），返回退订链接。
+
+    优先返回 http(s) 链接（可作按钮直接打开），没有则退回 mailto: 链接。
+    示例头: <https://x.com/unsub>, <mailto:unsub@x.com>
+    """
+    if not header_value:
+        return ""
+    # 标准格式是尖括号包裹的 URL 列表，逐个提取
+    urls = re.findall(r"<([^>]+)>", header_value)
+    if not urls:
+        # 兼容无尖括号的裸格式，按逗号切分后取 http/mailto
+        urls = [u.strip() for u in header_value.split(",")]
+    http_url = ""
+    mailto_url = ""
+    for u in urls:
+        u = u.strip()
+        if u.startswith(("http://", "https://")):
+            http_url = u
+            break
+        if u.startswith("mailto:"):
+            mailto_url = u
+    return http_url or mailto_url
+
+
 _PROVIDERS_NEED_ID = ("163.com", "126.com")
 
 
@@ -171,11 +197,12 @@ def fetch_unseen_emails(account: EmailAccount, skip_uids: set[bytes] | None = No
                     date_str = msg.get("Date", "")
                     body = _get_text_from_msg(msg)
                     body_len = len(body)
+                    list_unsubscribe = _parse_list_unsubscribe(msg.get("List-Unsubscribe", ""))
 
                     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,
-                                        folder=folder, cc=cc))
+                                        folder=folder, cc=cc, list_unsubscribe=list_unsubscribe))
 
                     # FETCH 可能被服务器自动标已读，立即标回未读
                     conn.uid("STORE", uid, "-FLAGS", "\\Seen")

src/summarizer.py

@@ -46,7 +46,8 @@ def ai_process(cfg: Config, user: UserConfig, acct_idx: int, mail: Email, tg_msg
 
     # 阶段2：AI 处理，更新为思考中
     edit_message(cfg.bot_token, user.chat_id, tg_msg_id, f"🤖 *AI思考中…*\n{label}")
-    summary = summarize_email(user.ai, mail.recipient, mail.subject, mail.sender, mail.body, mail.account_email)
+    summary = summarize_email(user.ai, mail.recipient, mail.subject, mail.sender,
+                              mail.body, mail.account_email, mail.list_unsubscribe)
     summary["recipient"] = mail.recipient
     if "@" not in summary.get("sender", ""):
         summary["sender"] = mail.sender
@@ -65,6 +66,7 @@ def ai_process(cfg: Config, user: UserConfig, acct_idx: int, mail: Email, tg_msg
         "account_email": mail.account_email,
         "uid": mail.uid,
         "folder": mail.folder,
+        "list_unsubscribe": mail.list_unsubscribe,
         "thinking_msg_id": tg_msg_id if tg_msg_id else 0,
     }
 
@@ -74,11 +76,13 @@ def tg_send_and_mark(cfg: Config, user: UserConfig, info: dict):
     acct = user.email_accounts[info["acct_idx"]]
     thinking_msg_id = info.get("thinking_msg_id")
     if thinking_msg_id:
-        from src.tg_bot import _summary_keyboard
+        from src.tg_bot import _summary_keyboard, _ensure_unsub_link
         from src.database import save_email_context
         can_reply = info["data"].get("can_reply", True)
         is_promotion = info["data"].get("category") == "promotion"
-        links = info["data"].get("links", [])
+        # AI 漏提取退订链接时，用 List-Unsubscribe 头兜底补上
+        links = _ensure_unsub_link(info["data"].get("links", []), info.get("list_unsubscribe", ""))
+        info["data"]["links"] = links
         edit_message(cfg.bot_token, user.chat_id, thinking_msg_id,
                      info["text"], _summary_keyboard(can_reply, is_promotion, links))
         save_email_context(thinking_msg_id, {
@@ -105,7 +109,8 @@ def tg_send_and_mark(cfg: Config, user: UserConfig, info: dict):
                      original_sender=info.get("original_sender", ""),
                      original_recipient=info.get("original_recipient", ""),
                      original_reply_to=info.get("original_reply_to", ""),
-                     account_email=info.get("account_email", ""))
+                     account_email=info.get("account_email", ""),
+                     list_unsubscribe=info.get("list_unsubscribe", ""))
     # 标记已读放到后台线程
     def _bg_mark():
         try:

src/tg_bot.py

@@ -22,10 +22,12 @@ def send_summary(bot_token: str, chat_id: str, summary_text: str,
                  summary_data: dict, original_body: str, account_idx: int,
                  original_sender: str = "", original_recipient: str = "",
                  original_reply_to: str = "", account_email: str = "",
-                 original_cc: str = "") -> int:
+                 original_cc: str = "", list_unsubscribe: str = "") -> int:
     can_reply = summary_data.get("can_reply", True)
     is_promotion = summary_data.get("category") == "promotion"
-    links = summary_data.get("links", [])
+    # AI 漏提取退订链接时，用 List-Unsubscribe 头兜底补上
+    links = _ensure_unsub_link(summary_data.get("links", []), list_unsubscribe)
+    summary_data["links"] = links
     # summary_data 里可能有 cc
     if original_cc:
         summary_data["cc"] = original_cc
@@ -217,9 +219,14 @@ def _link_buttons(links: list | None) -> list:
     rows = []
     for link in unsub_links + other_links:
         url = link.get("url", "")
-        # 校验 URL：合法 http/https，无多重协议头，长度合理。
+        # 校验 URL：http/https 需无多重协议头；mailto: 仅用于退订场景（如 mailto:x@y.com?subject=Unsubscribe）
-        # 退订链接常带长 tracking 参数（实测 OpenAI 的 >700 字符），上限放宽到 2048
+        if url.startswith("http"):
-        if not (url.startswith("http") and url.count("://") == 1 and len(url) < 2048):
+            valid = url.count("://") == 1 and len(url) < 2048
+        elif url.startswith("mailto:"):
+            valid = len(url) < 2048
+        else:
+            valid = False
+        if not valid:
             continue
         text = (link.get("text") or "").strip()[:30]
         if not text:
@@ -229,6 +236,25 @@ def _link_buttons(links: list | None) -> list:
     return rows
 
 
+def _ensure_unsub_link(links: list, list_unsubscribe: str = "") -> list:
+    """AI 未提取到退订链接时，用邮件头 List-Unsubscribe 的链接兜底补一个退订按钮。
+
+    仅当 links 中没有任何退订类链接且头部确实有可用的 http(s)/mailto 链接时生效。
+    """
+    if any(_is_unsub_link(l) for l in links):
+        return links
+    url = (list_unsubscribe or "").strip()
+    if url.startswith("http"):
+        valid = url.count("://") == 1 and len(url) < 2048
+    elif url.startswith("mailto:"):
+        valid = len(url) < 2048
+    else:
+        valid = False
+    if valid:
+        return [{"text": "退订", "url": url}] + list(links)
+    return links
+
+
 def _summary_keyboard(can_reply: bool = True, is_promotion: bool = False, links: list | None = None) -> dict:
     if is_promotion:
         kb = []

tests/test_unsub_keyboard.py

@@ -1,6 +1,11 @@
 """测试摘要键盘渲染：推广邮件的退订链接按钮必须显示且排最前。"""
 
-from src.tg_bot import _is_unsub_link, _link_buttons, _summary_keyboard
+from src.tg_bot import (
+    _ensure_unsub_link,
+    _is_unsub_link,
+    _link_buttons,
+    _summary_keyboard,
+)
 
 
 def _rows_of(kb: dict) -> list[list[dict]]:
@@ -102,4 +107,43 @@ def test_oversized_url_filtered():
     url = "https://example.com/" + "x" * 2100
     links = [{"text": "退订", "url": url}]
     rows = _link_buttons(links)
-    assert rows == []
+    assert rows == []
+
+
+def test_mailto_unsub_link_rendered():
+    """mailto: 退订链接（如 InferX 的 mailto:team@inferx.net?subject=Unsubscribe）必须渲染"""
+    links = [{"text": "退订", "url": "mailto:team@inferx.net?subject=Unsubscribe"}]
+    kb = _summary_keyboard(can_reply=False, is_promotion=True, links=links)
+    rows = kb["inline_keyboard"]
+    assert rows[0][0]["url"] == "mailto:team@inferx.net?subject=Unsubscribe"
+    assert "🔕" in rows[0][0]["text"]
+    assert _is_unsub_link(links[0])
+
+
+def test_ensure_unsub_link_http_header_fallback():
+    """AI 没提取到退订链接时，用 List-Unsubscribe 头的 http 链接兜底"""
+    header = "https://links.iterable.com/s/uh/tKjpy4SHCKvbzE2votNyZEJDvlMdeodVyWFExNs310ugJ_RvZtoZq4gGLQ0BXMSL2lf3kEZsmr1XJmrODIFHpEwcypo3LR096pZ7jsfBynZBgGWz171Wc1E6ZIIC5Lu0e-Stq6p5-_Ad3CnNlUWrW1tnrLSeiGsOiQG_zMYKVbtfQZgvfm3QYfD9lQ/Cey29KU8yOzIUltaEJA8EMRFf-FKMZQy/24"
+    links = _ensure_unsub_link([], header)
+    assert links == [{"text": "退订", "url": header}]
+    kb = _summary_keyboard(can_reply=False, is_promotion=True, links=links)
+    assert kb["inline_keyboard"][0][0]["url"] == header
+
+
+def test_ensure_unsub_link_mailto_header_fallback():
+    """List-Unsubscribe 头只有 mailto 时也兜底"""
+    header = "mailto:unsubscribe+19693436+25822730@unsubscribe.iterable.com"
+    links = _ensure_unsub_link([], header)
+    assert links == [{"text": "退订", "url": header}]
+
+
+def test_ensure_unsub_link_no_duplicate_when_ai_extracted():
+    """AI 已提取退订链接时，不重复添加头部链接"""
+    ai_links = [{"text": "取消订阅", "url": "https://r.openai.com/asm/unsubscribe/?x=1"}]
+    links = _ensure_unsub_link(ai_links, "https://links.example.com/unsub")
+    assert links == ai_links
+
+
+def test_ensure_unsub_link_ignores_invalid_header():
+    """头部无有效链接时不兜底"""
+    assert _ensure_unsub_link([], "") == []
+    assert _ensure_unsub_link([], "javascript:alert(1)") == []