AW4 — Finalize real-world compatibility baseline and accepted failure policy

[joris97jansen]

Description

Finalize the real-world static page compatibility baseline from AU.

This issue should decide which captured real-world pages are included in the release baseline, which are blockers, which are accepted-known failures, and which are deferred due to unsupported dynamic/browser-platform behavior.

The goal is to make real-world compatibility claims reproducible and not dependent on anecdotal testing.

Requirements

• Add release compatibility corpus manifest.

• Include static page categories from AU.

• Define release-critical corpus subset.

• Define extended/non-blocking corpus subset.

• Freeze captured resources for release.

• Freeze environment/viewport settings for release tests.

• Add compatibility result summary.

• Classify each corpus page:

  • release pass;

  • release warning;

  • accepted-known failure;

  • unsupported due to JavaScript/app-shell dependency;

  • unsupported due to deferred platform feature;

  • release blocker.

• Add subsystem failure classification.

• Link minimized regression fixtures where available.

• Link GitHub issues for unresolved blockers.

• Add accepted failure rationale for every accepted failure.

• Add no-JS compatibility summary.

• Add cross-engine comparison summary where available.

• Add deterministic compatibility report.

• Document policy for adding/removing corpus entries after release.

Exit Criteria

• Release compatibility corpus is frozen.

• Compatibility results are reproducible.

• Accepted failures have rationale.

• Release blockers are visible.

• Unsupported JS/dynamic cases are classified honestly.

• Cross-engine comparison summary exists where available.

• The issue is closeable without claiming complete real-world web compatibility.