* WhatsApp: harden auth persistence and backup recovery
* WhatsApp: model unstable auth state across runtime and setup
* WhatsApp: recover login and monitor startup from unstable auth
* Channels: surface auth stabilizing in status and health
* Gateway protocol: add channels.start surface
* Gateway: reconcile local channel runtime after CLI login
* Channels UI: reflect recovered login start state
* Changelog: note WhatsApp auth stabilization
* Gateway: fix lint in call test