Debian versions must start with a digit. When called via 'make deb',
VERSION is passed from Makefile (git describe output includes 'v' prefix).
The strip was previously only done inside the auto-detection branch,
so 'make deb' produced invalid versions like 'v2026.07.30-2-g05604a8-1'.
Now VERSION= runs after the version is determined, regardless
of whether it came from an argument or auto-detection.
- Makefile: add 'deb' and 'release' targets; fix migrate/create syntax
- scripts/build-deb.sh: build .deb with systemd unit, postinst/prerm/postrm
- .github/workflows/ci.yml: go build, test, lint on PR/push to main
- .github/workflows/release.yml: multi-platform build (linux/darwin/windows
× amd64/arm64), .deb for Linux, tarballs, draft GitHub Release on tag v*
- README.md: add CI/Release badges, Install section with .deb and binary
release instructions