chore(ci): add GitHub Actions workflow for release process

* Implement test and release jobs for versioned tags
* Build binaries for multiple OS/architecture targets
* Create release and upload assets to GitHub
* Add release-version target in Makefile for version bumping

Makefile

@@ -4,7 +4,7 @@ CONFIG_DIR  := /etc/unitdore
 VERSION    := $(shell git describe --tags --always --dirty 2>/dev/null || echo "dev")
 LDFLAGS    := -ldflags "-X main.version=$(VERSION)"
 
-.PHONY: all build install uninstall test lint clean
+.PHONY: all build install uninstall test lint clean release-version
 
 all: build
 
@@ -40,6 +40,18 @@ lint:
 clean:
 	rm -f $(BINARY)
 
+## release-version: bump patch version, tag, and push to trigger release workflow
+release-version:
+	@CURRENT=$$(git describe --tags --abbrev=0 2>/dev/null || echo "v0.0.0"); \
+	MAJOR=$$(echo $$CURRENT | sed 's/v\([0-9]*\)\.\([0-9]*\)\.\([0-9]*\).*/\1/'); \
+	MINOR=$$(echo $$CURRENT | sed 's/v\([0-9]*\)\.\([0-9]*\)\.\([0-9]*\).*/\2/'); \
+	PATCH=$$(echo $$CURRENT | sed 's/v\([0-9]*\)\.\([0-9]*\)\.\([0-9]*\).*/\3/'); \
+	NEXT="v$$MAJOR.$$MINOR.$$((PATCH + 1))"; \
+	echo "Current: $$CURRENT → Next: $$NEXT"; \
+	git tag -a "$$NEXT" -m "Release $$NEXT"; \
+	git push origin "$$NEXT"; \
+	echo "Pushed tag $$NEXT — release workflow triggered"
+
 ## help: show this help
 help:
 	@grep -E '^## ' Makefile | sed 's/## /  /'