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/stock-analysis-skill/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "stock-analysis-skill",
+  "version": "1.0.0",
+  "description": "A股/港股/美股 决策仪表盘 + 传闻扫描 + 自选股提醒",
+  "main": "dist/index.js",
+  "scripts": {
+    "build": "tsc",
+    "analyze": "ts-node src/index.ts analyze",
+    "dividend": "ts-node src/index.ts dividend",
+    "rumors":   "ts-node src/index.ts rumors",
+    "watch":    "ts-node src/index.ts watch"
+  },
+  "dependencies": {
+    "z-ai-web-dev-sdk": "latest"
+  },
+  "devDependencies": {
+    "@types/node": "^20.0.0",
+    "typescript": "^5.0.0",
+    "ts-node": "^10.0.0"
+  }
+}