stage-13: WhatsApp bridge with Baileys + Python adapter

Node.js bridge (bridge/whatsapp/): Baileys client with Express HTTP API
on localhost:8098 — QR code linking, message queue, reconnection logic.

Python adapter (src/adapters/whatsapp.py): polls bridge every 2s, routes
through router.py, separate whatsapp.owner/admins auth, security logging.

Integrated in main.py alongside Discord + Telegram via asyncio.gather.
CLI: echo whatsapp status/qr. 442 tests pass (32 new, zero failures).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

config.json

@@ -3,7 +3,7 @@
     "name": "Echo",
     "default_model": "opus",
     "owner": "949388626146517022",
-    "admins": []
+    "admins": ["5040014994"]
   },
   "channels": {
     "echo-core": {
@@ -12,6 +12,13 @@
     }
   },
   "telegram_channels": {},
+  "whatsapp": {
+    "enabled": false,
+    "bridge_url": "http://127.0.0.1:8098",
+    "owner": null,
+    "admins": []
+  },
+  "whatsapp_channels": {},
   "heartbeat": {
     "enabled": true,
     "interval_minutes": 30