Build dynamic GitHub release notes

[Widthdom]

Summary

• Resolve the previous version from all published, stable GitHub Releases by published_at.
• Build deterministic release notes with a dynamic Full Changelog comparison and the nildiff install/update commands.
• Add regression coverage and keep the English/Japanese developer documentation and changelog aligned.

Why

The release workflow previously relied on GitHub-generated notes, which did not guarantee the requested note structure or an explicitly selected published predecessor.

Impact

Future releases use the latest published stable GitHub Release—not a local Git tag—as the comparison base and produce the requested consistent release-note format.

Verification

• Full Release test suite: 2,042 passed, 1 expected skip.
• Focused CiAutomationConfigurationTests: 21 passed.
• dotnet format FolderDiffIL4DotNet.sln --verify-no-changes --no-restore --verbosity minimal.
• Parsed .github/workflows/release.yml as YAML.
• Live GitHub Releases API smoke generation produced v1.21.0...v9.9.9 with the requested note structure.
• git diff --check.
• Adversarial review rounds completed.