Tags: modstart-lib/skillui

build: remove tar.gz and add version numbers to packaged artifacts

- Linux: use scripts/package-linux.sh (deb + AppImage) with versioned names
- Windows: SkillUI-<version>-windows-<goarch>.zip + renamed versioned installer
- macOS: SkillUI-<version>-darwin-<goarch>.dmg
- workflows match prochub structure (goarch matrix, VERSION extraction)
- test.yml simplified to pure build test (raw binary artifacts)

docs: update changelog for v0.2.0 release

init