{"ok":true,"channels":["stable","preview","engineering"],"endpoints":{"/check?channel=…[&current=…]":"HMAC-gated: returns full OTA offer including imageUrl","/info":"Public: returns version + date + changelog + FULL firmware URL for all 3 channels","/history[?channel=…]":"Public: per-channel history of every version this Worker has seen","/healthz":"Public: this"}}