feat(whatsapp): auto-provision Docker bridge per tenant

- Add Dockerfile.whatsapp-bridge with Baileys + env var support
- Modify whatsapp-bridge-server.js to accept PORT, TENANT_ID, WEBHOOK_BASE
- Add internal_bp.py with endpoints to provision/destroy bridges via Docker
- Register internal_bp in app.py
- Each tenant gets isolated container, port, and volume

pos/app.py

@@ -107,6 +107,9 @@ def create_app():
     from blueprints.supplier_portal_bp import supplier_portal_bp
     app.register_blueprint(supplier_portal_bp)
 
+    from blueprints.internal_bp import internal_bp
+    app.register_blueprint(internal_bp)
+
     # Health check
     @app.route('/pos/health')
     def health():