Sprint 15.6 — Add integration and regression coverage

[maruson08]

Problem / motivation

The immutable dependency, metadata workflow, and existing tools need deterministic regression protection.

Scope

Add small local JPEG/PNG/WebP fixtures and extend test registries for provenance, inspection, cleaning, verification, input/output, security, accessibility, responsive, i18n, and existing tool regressions.

Non-goals

No new test framework, network fixtures, package manager, or browser-test dependency.

Acceptance criteria

• Exact artifact hash and approved vendor contents are pinned.
• Inspection, opaque/decoded, partial, diagnostics, cleaning, ICC, immutability, deterministic output, verification fail-closed, naming, cancellation, and state retention are covered.
• Metadata code is enforced to avoid Canvas, unsafe DOM sinks, runtime URLs, version checks, and direct vendor imports outside metadata.js.
• node tests/run-all.mjs and git diff --check pass.

[maruson08]

Completed by PR #29, merged into the v2 integration branch at 82f09e8. GitHub did not apply the closing keyword automatically because v2 is not the repository default branch.