feat: IMAP mail sync with thread-to-contact matching (PRD §6.1)

Real IMAP connection via imapflow library:
- Connects to IMAP server (IMAPFlow, TLS on port 993)
- Fetches recent messages (configurable limit, default 20)
- Extracts: from, fromEmail, subject, date, snippet (200 chars)
- Thread-to-contact matching (PRD §6.1):
  1. Match sender email against persons table
  2. If no person match, extract domain and match against company.website
  3. Returns matchedCompany + matchedPerson for each email
- Audit-logged (action: crm.mailsync:imap)
- Zod validated (host, port, user, password, folder, limit)
- 502 on IMAP connection failure with detail
- 400 on validation failure

Tested: invalid creds → 502 'IMAP connection failed', missing host → 400

skills/gaokao-recommend-schools/examples/school_recommendation_template.json

@@ -0,0 +1,13 @@
+{
+  "school_strategy": "院校布局策略：冲/稳/保如何分配、重点院校举例（可用 <strong>）",
+  "recommended_schools": [
+    {
+      "university_name": "必须与 parsed.json 完全一致",
+      "university_code": "必须与 parsed.json 完全一致",
+      "modal": {
+        "title": "学校推荐原因：院校名称",
+        "body": "<h4>推荐原因</h4><ul><li><strong>地域优势：</strong>...</li><li><strong>院校层次：</strong>...</li><li><strong>专业契合：</strong>与 major_recommendation 的关联</li><li><strong>录取性价比：</strong>...</li></ul>"
+      }
+    }
+  ]
+}