v0.4.1

macOS release binaries are now Developer ID signed and notarized. Background jobs
installed with regesto schedule install can therefore be attributed to the identified
developer instead of appearing in System Settings as items from an unidentified developer.

Release preparation now runs on the signing Mac and stops with reviewable archives and
checksums before any publication. Publishing remains an explicit second command and then
starts the Homebrew tap's existing secret-free updater. Apple signing certificates and
notarization credentials are never copied into GitHub Actions. Linux binaries and the
installation commands are unchanged.