ci(release): automate versioning from CHANGELOG.md

Replace manual version input with automatic extraction from
CHANGELOG.md. Release notes are now pulled directly from the
changelog entry for the version being released.

feat(release): add code signing and notarization to GitHub Actions wo…

…rkflow

Enable Developer ID signing and Apple notarization for release builds.
Updates documentation to reflect signed distribution.

feat(ci): build universal binary for Intel and Apple Silicon

Add x86_64 and arm64 architectures to xcodebuild command to create a
universal binary that runs natively on both Intel and Apple Silicon Macs.