ci: automate CentOS 9 x86_64 rpm link validation (#104)

* ci: automate CentOS 9 x86_64 rpm link validation

* ci: harden rpm link validator workflow for zizmor

* fix: avoid regex backref collision in rpm link updater

* ci: bump harden-runner to v2.16.0

* feat: refine rpm URL fallback decision flow

* chore: simplify rpm validator status output format

* chore: stream rpm validator logs in GitHub Actions

* chore: refine rpm validator output - PASS/FAIL with tab formatting

* chore: finalize rpm validator output format

* chore: reorder rpm validator output to PASS/FAIL first

* fix: validate builddeps url before adding on version update

Author: dmkarthi