proposal: explore a Vitest reporter without coupling the core

[luantaraschi]

Goal

Explore how Eventlaw counterexamples could appear naturally in Vitest output while keeping the core independent of test runners.

Questions

• Is a reporter, matcher, helper, or optional package the smallest useful boundary?
• How should pass, fail, pending, and vacuous results map to test output?
• How are minimized traces attached without losing structured data?
• Can the integration remain an optional subpath with no core dependency?

Deliverable

A design note or minimal spike using a real test. Do not add a runtime dependency to the main eventlaw entry.