cargo-mailbox-management

Send mail from inboxes Cargo owns — provision mailboxes on a sending domain, run provider warm-up and the 5→40/day send ramp, deliver with the `sendEmail` action, and read back threads, replies, delivery events, and the workspace suppression list. Triggers: "set up a sending mailbox", "provision inboxes for outbound", "warm up this mailbox", "how many sends do I have left today", "send this from Cargo", "did they reply", "who unsubscribed", "suppress this recipient", "take me off your list", "never email them again", "what do mailboxes cost", "my mailbox is stuck pending". A mailbox is a recur