Make compact proof contracts declaration-only

[iperev]

Summary

• replace assurance-shaped compact proof fields with a declaration-only v2 contract
• preserve full binding identity and role-qualified witness-route identity across resolver, impact, coverage, view, adoption, and pilot projections
• close exact v1-to-v2 wire and parent-contract migration with frozen observations and release-owner foreign keys
• add conservative release-build source-candidate closure without claiming runtime invocation or consumer completeness
• advance the package and release change record to 0.4.0 and close COMPACT-01

Proof

• npx --yes npm@11.18.0 run check
• go test -race ./internal/kernel/compactproofcontract ./internal/command/impact ./internal/command/conformanceprofile ./internal/command/requirementimpactinput ./internal/command/requirementcoverageview ./internal/app -run 'Compact|WitnessRoute|Impact|Conformance|Coverage' -count=1
• go mod tidy -diff
• npm run command-contract:check
• npm run command-family:check
• frozen 66-file closeout target and verified academic invariant bundle

Non-claims

• declaration routes do not prove selector resolution, oracle quality, witness execution, mutation adequacy, findings, freshness, trust, merge approval, rollout, or production readiness
• local candidate closeout does not prove registry publication or provider attestations