icv-trace documentation

Start with the package README for installation and a small operation. These documents describe the stable v1 boundary in consumer terms.

• Contracts defines accepted operation facts, policy and limits, records, output health, context, supervision and compatibility.
• Human renderer shows the readable projection for services, commands, tasks and pipelines.
• examples/human_trace.py is a runnable, dependency-free command/pipeline/service example, including a simulated supervisor observation.

These are the normative public package contracts. They retain their incubation source revision for provenance; changes to this package update these documents as part of the same release.