ci: add GitHub Actions test pipeline and GoReleaser releases for oo

Mirror eSlider/go-config: release-please for semver, tag-triggered GoReleaser
builds cross-platform oo binaries with embedded version metadata.

Co-authored-by: Cursor <cursoragent@cursor.com>

cmd/oo/version.go

@@ -0,0 +1,8 @@
+package main
+
+// Build metadata injected at release time via -ldflags (GoReleaser).
+var (
+	version = "dev"
+	commit  = "none"
+	date    = "unknown"
+)