Clear all queued messages in a thread at once

[WhiteWarrior625]

Queued messages pile up in a thread (missed runs, stale steering, retries). I have threads with 50+ queued messages right now.

Today the only way to remove them is one at a time: t3_queue_cancel takes a single queuedRunId, and the composer offers no bulk action. Settling one of these threads means wading through dozens of individual cancels.

Please add a way to clear all queued messages in a thread in one step:

• A t3_queue_clear operation for a thread (optionally filtered by status or text match), and/or
• A "clear all" affordance in the composers queued-messages list.

That would make it practical to settle long-neglected threads instead of abandoning them.