chore(ci): expand branch filters + enforce golden validation

[macroflux]

Summary

Tasks

• Update .github/workflows/tests.yml to trigger on:
  • pull_request: [dev, main, release/**]
  • push: [dev, feat/, exp/]
• Add validator strict example flag.
• Ensure exit codes 2/3 mapped to failure.

Acceptance

CI triggers on all PRs; validator enforced; branch protection rules updated.

Area

ci

Priority

medium