Mount Docker socket in GitHub runner for container builds

Enables docker/docker-buildx builds by mounting the host's Docker socket.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: cmyui

k8s/github-runner/templates/deployment.yaml

@@ -35,4 +35,12 @@ spec:
                   key: token
           resources:
             {{- toYaml .Values.resources | nindent 12 }}
+          volumeMounts:
+            - name: docker-sock
+              mountPath: /var/run/docker.sock
+      volumes:
+        - name: docker-sock
+          hostPath:
+            path: /var/run/docker.sock
+            type: Socket
       terminationGracePeriodSeconds: 60