feat(v2): add native WhatsApp adapter using Baileys v6

Direct ChannelAdapter implementation — no Chat SDK bridge.
Ports v1 infrastructure: getMessage fallback, outgoing queue,
group metadata cache, LID-to-phone mapping, auto-reconnect.
Auth via pairing code (WHATSAPP_PHONE_NUMBER) or QR code.

Text messaging only (MVP). Not yet implemented:
- File/image attachments (send and receive)
- Edit message, delete message
- Reactions
- Bot echo filtering (own messages loop back as inbound)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

package.json

@@ -34,10 +34,14 @@
     "@chat-adapter/whatsapp": "^4.24.0",
     "@onecli-sh/sdk": "^0.3.1",
     "@resend/chat-sdk-adapter": "^0.1.1",
+    "@types/qrcode": "^1.5.6",
+    "@whiskeysockets/baileys": "^6.7.21",
     "better-sqlite3": "11.10.0",
     "chat": "^4.24.0",
     "chat-adapter-imessage": "^0.1.1",
-    "cron-parser": "5.5.0"
+    "cron-parser": "5.5.0",
+    "pino": "^9.6.0",
+    "qrcode": "^1.5.4"
   },
   "devDependencies": {
     "@eslint/js": "^9.35.0",