* ci: harden workflows with credential isolation, template injection defenses, and dependabot cooldown
- Add persist-credentials: false across all actions/checkout invocations
- Eliminate template injection by mapping matrix and input variables to env: in freebsd.yml, release.yml, and sonarcloud.yml
- Add 7-day cooldown to dependabot.yml to protect against supply-chain compromise of recently published releases
- Update test suite to validate hardened environment mappings
* ci: allow static.crates.io and registry endpoints in gate and windows-arm64 runners