docs(changelog): evidence section

[hkimw]

Summary

• Add an Unreleased Keep-a-Changelog entry for the open v002.1 ramp PR set feat(trace): add kv260 trace readback contract #160-docs(readme): refresh root readme with today's capabilities #174.
• Group the PRs under Trace readback, Framing, Analyzer, Dashboard, Visualizer, Fixtures, and Docs.
• Keep the entry scoped to contracts, parsers, local artifacts, fixtures, and docs with an explicit no-release/no-target-readiness/no-live-capture/no-performance claim guard.

Validation

• git diff --check
• unique PR refs counted in CHANGELOG.md diff: 15 (feat(trace): add kv260 trace readback contract #160-docs(readme): refresh root readme with today's capabilities #174)
• no Rust or TypeScript files changed; cargo check and npx tsc --noEmit were not required for this docs-only slice.

Claim guard

• The changelog says the listed PRs were open as of 2026-05-07.
• It does not claim release availability, target readiness, live capture evidence, or performance results.