[IchenDEV]

Summary

This PR updates the GitHub Actions release pipeline to publish DMG artifacts instead of the raw SwiftPM executable.

• switch the tag-based Release workflow to run ./scripts/package-dmg.sh
• publish a versioned SkillsUI-<version>-macos-arm64.dmg plus its .sha256 checksum to GitHub Releases
• update the main branch artifact workflow to upload dist/SkillsUI.dmg and checksum instead of .build/release/SkillsUI

Why

The repo already has a working local DMG packaging script, but CI was still calling swift build -c release and uploading the bare binary or a tar.gz built from it. That is why GitHub-hosted release artifacts still did not match the standard drag-to-Applications install flow.

Validation

• locally simulated the release workflow with:
  • APP_VERSION=1.2.3 APP_BUILD=456 ./scripts/package-dmg.sh
  • mv dist/SkillsUI.dmg dist/SkillsUI-1.2.3-macos-arm64.dmg
  • shasum -a 256 dist/SkillsUI-1.2.3-macos-arm64.dmg > dist/SkillsUI-1.2.3-macos-arm64.dmg.sha256
• confirmed the resulting DMG and checksum were created successfully

Notes

• this changes future CI outputs; already-published release assets will not retroactively become DMGs
• to get a DMG on GitHub Releases, a new v* tag run is still required after this PR merges