Separate declarations from proof assurance - #87

Summary

• Replace assurance-sounding caller metadata with declaration-only evidence, falsifier, oracle-signal, supersession, and coverage vocabulary.
• Preserve digest-bound requirement-authoring references and make migration parity explicitly caller-declared, including lossless record-level non-claims.
• Advance requirement coverage output to v2 with exact root and row admission, complete retained test projections, canonical wire text, parent and diagnostic closure, and a coverageBasis commitment for owner scope and retained inventory.
• Bind release coverage metrics to the actual CLI contract command inventory and protect high-risk scenarios with exact witness selectors.
• Synchronize requirements, bindings, CLI contract, generated projections, ABI hashes, package version 0.3.0, and the machine-readable change record.
• Repair the browser focus-contrast oracle without weakening accessibility assertions.

Proof

• npx --yes npm@11.18.0 run check
• go test -race ./internal/command/migrationparityadmission ./internal/command/requirementcoverageview ./internal/tools/coveragemetrics ./internal/tools/releasechange -count=1
• New high-risk coverage closure falsifiers repeated 10 times
• go run ./internal/tools/commandcontractgen --check
• git diff --check
• Self-hosting closeout: 69/69 requirements, 181 scenarios, 78 commands
• Browser proof: 93/93 tests across Chromium, Firefox, and WebKit

Review Closure

Two frozen-diff review cycles covered runtime re-admission and public-contract/release authority. The first cycle found three closure gaps: non-canonical wire values, incomplete exact-selector coverage, and dropped migration-parity record non-claims. All three were corrected, the complete gate was rerun, and a fresh-context final cycle reported no findings on the corrected object.

Deferred Work

The temporary requirement-source-v2 design and implementation plan remain local and are intentionally excluded from this PR. A textual DSL or grouped source representation remains a bounded measured experiment; this change does not introduce a second source of truth or a second production parser.

Non-Claims

This PR does not prove native selector execution quality, evidence freshness or authenticity, provider CI completion, registry publication, deployment, rollout, or production readiness. Declaration routes remain mapping metadata and do not become assurance.