[Task]: Track and report conformance (passing vs. failing tests)

[michael-duren]

What needs to be done

Make conformance progress visible: track which validation tests pass vs. fail
over time so improvement against the runtime-spec is measurable.

Options to evaluate and pick from:

• Parse the suite's TAP output into a pass/fail summary (counts + per-test status).
• Publish the summary somewhere durable: a generated docs/conformance.md, a
  CI job summary, or a badge in the README.
• Optionally snapshot a baseline so regressions (a previously-passing test going
  red) are detectable.

Keep it lightweight — the point is a trend line, not a dashboard.

Acceptance criteria

• Suite output is parsed into a pass/fail summary (total passing / failing / skipped)
• The summary is published somewhere contributors can see it (README badge, docs page, or CI summary)
• A baseline snapshot exists so regressions can be spotted
• How to regenerate the report is documented

Parent / tracking issue

Part of the OCI runtime validation epic.

Blocked by

• Run the validation suite in CI as a non-blocking job

Rough size

S — a few hours