fix: repair arm64 release packaging

[bkataru]

Summary

• configure Ubuntu ports as the arm64 apt source before installing Linux ARM64 cross packages
• constrain the default Ubuntu sources to amd64 so apt no longer requests arm64 packages from archive/security.ubuntu.com paths that 404
• document the v0.5.22 release workflow fix in the changelog

Verification

• python3 -c 'from pathlib import Path; import yaml; yaml.safe_load(Path(".github/workflows/release.yml").read_text()); print("release yaml ok")'
• parsed the release workflow run block and confirmed the heredoc delimiters are not indented after YAML parsing
• release run #27494051011 failed before publish on arm64 apt 404s, so no crates were published before this fix

Linear: DIR1-94