feat(ci): Gitea Actions release workflow on v* tags

Builds and pushes three images per tag, then runs helm upgrade
against us-prod. Cache-from/cache-to layers reuse buildx cache
across runs.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitea/workflows/release.yml

@@ -0,0 +1,96 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+env:
+  REGISTRY: git.ezscale.cloud
+  IMAGE_BASE: ezscale/website
+
+jobs:
+  build-release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Get version from tag
+        id: version
+        run: echo "VERSION=${GITHUB_REF#refs/tags/}" >> $GITHUB_OUTPUT
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to Gitea registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.CI_TOKEN }}
+
+      - name: Build and push app image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          target: app
+          push: true
+          cache-from: type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_BASE }}:cache-app
+          cache-to: type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_BASE }}:cache-app,mode=max
+          tags: |
+            ${{ env.REGISTRY }}/${{ env.IMAGE_BASE }}:app-${{ steps.version.outputs.VERSION }}
+            ${{ env.REGISTRY }}/${{ env.IMAGE_BASE }}:app-latest
+
+      - name: Build and push horizon image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          target: horizon
+          push: true
+          cache-from: type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_BASE }}:cache-horizon
+          cache-to: type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_BASE }}:cache-horizon,mode=max
+          tags: |
+            ${{ env.REGISTRY }}/${{ env.IMAGE_BASE }}:horizon-${{ steps.version.outputs.VERSION }}
+            ${{ env.REGISTRY }}/${{ env.IMAGE_BASE }}:horizon-latest
+
+      - name: Build and push scheduler image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          target: scheduler
+          push: true
+          cache-from: type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_BASE }}:cache-scheduler
+          cache-to: type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_BASE }}:cache-scheduler,mode=max
+          tags: |
+            ${{ env.REGISTRY }}/${{ env.IMAGE_BASE }}:scheduler-${{ steps.version.outputs.VERSION }}
+            ${{ env.REGISTRY }}/${{ env.IMAGE_BASE }}:scheduler-latest
+
+  deploy-us:
+    runs-on: ubuntu-latest
+    needs: build-release
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Get version from tag
+        id: version
+        run: echo "VERSION=${GITHUB_REF#refs/tags/}" >> $GITHUB_OUTPUT
+
+      - name: Install helm
+        uses: azure/setup-helm@v4
+        with:
+          version: v3.15.0
+
+      - name: Configure kubeconfig
+        run: |
+          mkdir -p ~/.kube
+          echo "${{ secrets.KUBECONFIG_US_PROD }}" | base64 -d > ~/.kube/config
+          chmod 600 ~/.kube/config
+
+      - name: Deploy to us-prod
+        run: |
+          helm upgrade --install ezscale-website ./helm/ezscale-website \
+            --namespace ezscale \
+            -f helm/ezscale-website/values-us-prod.yaml \
+            --set image.tag=${{ steps.version.outputs.VERSION }} \
+            --wait \
+            --timeout 10m