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

.gitea/workflows/release.yml

@@ -0,0 +1,57 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - name: Test
+        run: go test ./...
+
+      - name: Lint
+        run: go vet ./...
+
+  release:
+    needs: test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - name: Build release binaries
+        run: |
+          VERSION="${GITHUB_REF_NAME}"
+          for target in "linux/amd64" "linux/arm64" "darwin/amd64" "darwin/arm64" "windows/amd64"; do
+            GOOS="${target%/*}"
+            GOARCH="${target#*/}"
+            EXT=""
+            [ "$GOOS" = "windows" ] && EXT=".exe"
+            NAME="unitdore-${GOOS}-${GOARCH}${EXT}"
+            GOOS="$GOOS" GOARCH="$GOARCH" go build \
+              -ldflags "-X main.version=${VERSION}" \
+              -o "$NAME" .
+            echo "Built $NAME"
+          done
+
+      - name: Create release and upload assets
+        uses: softprops/action-gh-release@v2
+        with:
+          files: unitdore-*
+          generate_release_notes: true
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}