docs: restore Repology packaging badge - #3133

Overview

Restore the Repology packaging status badge in the installation documentation now that repology.org is back online.

Fixes #3119

Details

Uncomment the badge and remove the obsolete domain-outage TODO and temporary link-check suppression. Both the badge URL and its destination pass local checks with the same markdown-link-check version used by CI.

Documentation preview: https://manenim.github.io/osv-scanner/installation/

Testing

• markdown-link-check@3.15.0 docs/installation.md: all 11 links pass, including both Repology URLs.
• CI=true ./scripts/run_formatters.sh: repository-wide formatting passes.
• Existing Jekyll Pages workflow: build and deployment pass; rendered badge verified in the preview.
• git diff --check: passes.
• ./scripts/run_lints.sh: zero issues.
• make test VCR=ReplayOnly: passes (2,100 tests total, 14 skipped).

Checklist

• I have signed the Contributor License Agreement.
• I have read the CONTRIBUTING guide, and understand when to open a pull request
• I have run the linter using ./scripts/run_lints.sh.
• I have run the unit tests using ./scripts/run_tests.sh.
• I have made my commits and PR title follow the Conventional Commits specification.