ci: add release job that builds ndkcli for arm64 and x86_64

Triggers on version tags (v*). Builds stripped Android binaries for
both architectures, then creates a GitHub release with the binaries
attached. Depends on test and check-examples jobs passing first.

Author: xaionaro@dx.center

.github/workflows/ci.yml

@@ -3,12 +3,13 @@ name: CI
 on:
   push:
     branches: [main]
+    tags: ['v*']
   pull_request:
     branches: [main]
   workflow_dispatch:
 
 permissions:
-  contents: read
+  contents: write
 
 env:
   ANDROID_NDK_VERSION: r28
@@ -88,3 +89,49 @@ jobs:
           target: google_apis
           arch: x86_64
           script: make e2e-examples
+
+  release:
+    name: Release ndkcli
+    runs-on: ubuntu-latest
+    needs: [test, check-examples]
+    if: startsWith(github.ref, 'refs/tags/v')
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version: "1.24"
+
+      - name: Install Android NDK
+        run: |
+          wget -q "https://dl.google.com/android/repository/android-ndk-${ANDROID_NDK_VERSION}-linux.zip" -O /tmp/ndk.zip
+          unzip -q /tmp/ndk.zip -d /tmp/ndk-extract/
+          mkdir -p "$ANDROID_HOME/ndk"
+          mv /tmp/ndk-extract/android-ndk-* "$ANDROID_HOME/ndk/${ANDROID_NDK_DIR_NAME}"
+          echo "ANDROID_NDK_HOME=$ANDROID_HOME/ndk/${ANDROID_NDK_DIR_NAME}" >> "$GITHUB_ENV"
+          echo "NDK_CC_PREFIX=$ANDROID_HOME/ndk/${ANDROID_NDK_DIR_NAME}/toolchains/llvm/prebuilt/linux-x86_64/bin" >> "$GITHUB_ENV"
+
+      - name: Build ndkcli for arm64
+        run: |
+          CGO_ENABLED=1 GOOS=android GOARCH=arm64 \
+            CC="${NDK_CC_PREFIX}/aarch64-linux-android35-clang" \
+            go build -trimpath -ldflags="-s -w" \
+            -o ndkcli-android-arm64 ./cmd/ndkcli/
+
+      - name: Build ndkcli for x86_64
+        run: |
+          CGO_ENABLED=1 GOOS=android GOARCH=amd64 \
+            CC="${NDK_CC_PREFIX}/x86_64-linux-android35-clang" \
+            go build -trimpath -ldflags="-s -w" \
+            -o ndkcli-android-x86_64 ./cmd/ndkcli/
+
+      - name: Create release
+        env:
+          GH_TOKEN: ${{ github.token }}
+          TAG_NAME: ${{ github.ref_name }}
+        run: |
+          gh release create "$TAG_NAME" \
+            --title "ndkcli $TAG_NAME" \
+            --generate-notes \
+            ndkcli-android-arm64 \
+            ndkcli-android-x86_64