Publish pipeline: goreleaser + Maven Central + npm (#1)

* feat(cli): add Version var and version subcommand

* build(gradle): introduce uatu.version property for lockstep releases

* build(sdk-android): swap GitHub Packages for vanniktech Maven Central plugin

* build(spec-api): make package publish-ready for npm

* ci(release): add goreleaser config for cross-platform uatu CLI builds

* ci: add ci and release GitHub Actions workflows

* ci: restrict ci.yml to PR + workflow_dispatch (no direct push to master)

* docs(release): add local release targets, env example, and install docs

* build(sdk-android): make signAllPublications conditional on signing key

* ci(release): stage sidecar JAR at embed path before go build

* chore(spec-api): regenerate package-lock for updated package.json

* ci: install protoc-gen-go plugins before buf generate

* ci: bump Node to 22 (required for --experimental-strip-types)

.github/workflows/ci.yml

@@ -0,0 +1,72 @@
+name: ci
+
+on:
+  # Runs on PRs (opened / synchronize / reopened — the defaults) and manual
+  # dispatch only. We deliberately don't run on direct pushes to master:
+  # master is PR-merge-only, and PR validation already covers the merge
+  # commit via the `synchronize` event on the PR branch.
+  pull_request:
+  workflow_dispatch:
+
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+          cache: true
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: "17"
+
+      - name: Set up Android SDK
+        uses: android-actions/setup-android@v3
+
+      - name: Set up Node 22
+        uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+          cache: npm
+          cache-dependency-path: pkg/spec-api/package-lock.json
+
+      - name: Install buf
+        uses: bufbuild/buf-setup-action@v1
+
+      - name: Install protoc plugins
+        run: |
+          go install google.golang.org/protobuf/cmd/protoc-gen-go@latest
+          go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@latest
+          echo "$(go env GOPATH)/bin" >> "$GITHUB_PATH"
+
+      - name: Cache Gradle
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: gradle-${{ runner.os }}-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties') }}
+          restore-keys: |
+            gradle-${{ runner.os }}-
+
+      - name: Bootstrap
+        run: make bootstrap
+
+      - name: Lint proto
+        run: buf lint
+
+      - name: Go vet
+        run: go vet ./...
+
+      - name: Run tests
+        run: make test