[viethung0o0]

Summary

• Broadcasts stop automatically when the channel account is blocked from sending; series are paused too, and Resume shows a warning with the reason.
• Contact scan can be cancelled (UI and public API) and now waits according to the channel's API usage instead of sleeping in the worker.
• Inbox: failed messages can be resent (UI and public API); a send error is shown only after retries are exhausted.
• Messages typed quickly are sent one by one in order and held if one fails.

Test plan

• Unit and database integration tests for broadcast stop, scan cancel and retry, resend and the send queue
• Checked in the browser: stopped broadcast and Resume warning, scan cancel, resend of a failed message, sending from the inbox
• pnpm lint, type checks for database, business, worker and builder
• Check the Messenger 2022 error against real logs before merging