OpenCode emits session.error with MessageAbortedError when the user
interrupts a running turn. Paseo was mapping every session.error to
turn_failed, which set the agent lifecycle to error and appended a
raw JSON system error message to the timeline.
Now MessageAbortedError translates to turn_canceled (same as an
explicit cancel), so the agent returns to idle with no error state.
Real errors still produce turn_failed.
