feat: Add Kubernetes manifests for NetHack server

- Creates Kubernetes deployment, service, and PVC manifests to run a multiplayer NetHack server.
- Uses the pre-built matsuu/nethack-server:latest image.
- Configures the service to expose port 4000 externally and correctly route traffic to the container's port 23.
- Adds a .gitignore file to exclude temporary directories.

k8s/service.yaml

@@ -0,0 +1,13 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: nethack-service
+  namespace: nethack
+spec:
+  type: LoadBalancer
+  selector:
+    app: nethack
+  ports:
+    - protocol: TCP
+      port: 4000
+      targetPort: 23