cristhian
a95d804f0b
`set_cartesian_velocity` passed `duration=velocity_command_ttl_s` on every message, so each one re-armed a timed segment and the controller re-planned the same motion. On a real Lite6 that is not smooth travel: the arm moves in steps. Reducing how often the velocity is sent does not help — re-arming four times a second still steps — so it now uses `duration=0`, the SDK's "always effective, will not stop automatically", and skips a velocity that has not changed. One command stands until a different one replaces it. That removes the controller-side expiry, which `_expire_jog` was relying on: it flipped `_jogging` and reported `ready` without commanding anything, because the controller's own timer had already stopped the arm. With the velocity held indefinitely that would leave an arm travelling while the node reported idle, so `_expire_jog` now queues the stop itself. It goes through the job queue rather than the driver, since it runs on the reporter thread and the control thread owns the driver. `VELOCITY_COMMAND_TTL_S` is unchanged in value and meaning to a caller, but it is now enforced here rather than by the controller. Both halves are one commit on purpose: `duration=0` without the stop in `_expire_jog` is an arm that never stops when its sender dies. Adds tests/test_driver.py — the driver had no direct coverage, because FakeArm replaces it everywhere else, which is why this was invisible to the suite.