Define Trace v3 wire types and generated schemas while keeping protocol
1.1 peers compatible with 1.0. Default record start still produces Trace
v2, and only an explicit trace_version=3 request enables the new shape.
Refs #90
Co-authored-by: Cursor <cursoragent@cursor.com>
Tool cancellation is now cooperative end-to-end: the queue stays busy until compensation completes, cancellation is checked cooperatively across the pipeline, the fallback window is compensated too, and cleanup_failed is surfaced explicitly. Includes a gated delayed-compensation E2E test.
Ljy-0827