docs(parser): expand conformance source matrix

[stacknil]

Summary

• add explicit source-style coverage for Ubuntu/Debian auth.log, RHEL-family secure, and journalctl short-full
• add program/PAM-family style coverage for sshd, sudo, su, pam_unix, pam_faillock, and pam_sss
• update the changelog docs section

Validation

• git diff --check
• git diff --cached --check
• privacy/secret scan over changed files

Docs-only change; no parser behavior changed.