Remove automatic main push trigger from dev workflow (now only workflow_dispatch) and add a new release workflow (.github/workflows/release.yml). The release workflow triggers on tag pushes, builds artifacts for Linux, Windows and macOS using a matrix, sets up Python/uv, installs build tools (Nuitka/PyInstaller/UPX where needed), injects a short commit SHA into build_info.json, packages artifacts, uploads them, generates checksums, and creates a GitHub release with the built assets.