fix: 第三处app分支禁令同步改写——禁令集完整

Co-Authored-By: Claude Code <noreply@anthropic.com>

tests/test_lead_email_trigger.py

@@ -699,6 +699,19 @@ def test_reminder_app_contact_ask_gated_by_existing_contact():
     assert "reach out to you at your WhatsApp" in text   # 已留资版逐字脚本
 
 
+def test_reminder_app_contact_ask_confirmed_allows_missing_channel_once():
+    # Task 3 收尾: contact_note app+已留资分支的第三处禁令同步改写(禁令集完整)。
+    # 防空转设计: 双渠道齐 → 轻补 note 不注入;消息无价格词 → 边界分支不渲染;
+    # 此时"缺失渠道可按轻补指引提一次"只能来自该分支改写文本
+    # (:651 版是"仅可按",不构成子串)。
+    raw = {"联系方式": {"whatsapp": "+254712345678", "email": "a@b.com"}}
+    text = ConversationManager._build_context_reminder(
+        raw, "how can I contact you?", [], source="app")
+    assert "reach out to you at your WhatsApp" in text   # 已留资版逐字脚本在场
+    assert "缺失渠道可按轻补指引提一次" in text            # 第三处禁令改写钉死
+    assert "email address would help too" not in text     # 双渠道齐→无轻补注入(防空转)
+
+
 def test_reminder_app_contact_ask_without_contact_keeps_script():
     # App 会话未留资 → 原反向留资脚本原样保留
     text = ConversationManager._build_context_reminder(