fix(required-gate): honor disabled validation inputs

[ArchonVII]

Summary

• Honor disabled repo-required-gate validation inputs in the final decision job.
• Require optional dependency review, workflow validation, and policy validation only when both the caller input and classifier output enable them.
• Keep the PR contract CLI importable under Vitest while preserving the documented node scripts/pr-contract.mjs invocation path.

Verification

• npm test

command: npm test
location: local
result: pass: 5 test files, 77 tests
timestamp: 2026-06-02T01:37:50Z

• git diff --check

command: git diff --check
location: local
result: pass: no whitespace errors
timestamp: 2026-06-02T01:38:10Z

• node scripts/pr-contract.mjs --event-path %TEMP%\github-workflows-pr-contract-event-40.json --json

command: node scripts/pr-contract.mjs --event-path %TEMP%\github-workflows-pr-contract-event-40.json --json
location: local
result: pass: ok true, zero errors, zero warnings
timestamp: 2026-06-02T01:38:21Z

Verification Notes

The suite covers the new decision-job input wiring and confirms scripts/pr-contract.mjs remains importable by Vitest after the CLI compatibility adjustment.

Docs / Changelog

• README update not needed because the documented repo-required-gate / decision contract is preserved.
• Changelog fragment not needed because this repository does not define a changelog-fragment requirement for reusable workflow fixes.

Closes #40