Add GitHub Actions workflow to publish Helm chart to GHCR OCI

Packages chart/ and pushes to oci://ghcr.io/cpfarhood/charts on every
push to main that touches chart/** files.

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

.github/workflows/helm-release.yaml

@@ -0,0 +1,37 @@
+name: Publish Helm Chart
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'chart/**'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  packages: write
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Helm
+        uses: azure/setup-helm@v4
+
+      - name: Log in to GHCR
+        run: |
+          helm registry login ghcr.io \
+            --username ${{ github.actor }} \
+            --password ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Package chart
+        run: helm package chart/
+
+      - name: Push chart to GHCR
+        run: |
+          CHART_VERSION=$(helm show chart chart/ | grep '^version:' | awk '{print $2}')
+          helm push antigravity-${CHART_VERSION}.tgz oci://ghcr.io/cpfarhood/charts