v4.19.1: 🛠️ More resilient release checks

Fix release-check crash when GitHub has no latest tag

_pure_check_for_new_release no longer errors out when GitHub returns no latest release tag (for example when rate-limited). It now skips the version comparison and prints a concise warning (⚠ Unable to get latest Pure version.) instead, by @edouard-lopez in #427

Preview

What's Changed

• Automate release notes generation with Copilot CLI and document the release process in docs/RELEASE.md by @edouard-lopez in #424

Full Changelog: v4.19.0...v4.19.1