feat: add fleet autoscaling baseline

deploy/k8s/base/fleet-autoscaler.yaml

@@ -0,0 +1,17 @@
+apiVersion: autoscaling.agones.dev/v1
+kind: FleetAutoscaler
+metadata:
+  name: cosmic-clash-game
+  namespace: cosmic-clash
+  labels:
+    app.kubernetes.io/name: game-fleet-autoscaler
+spec:
+  fleetName: cosmic-clash-game
+  policy:
+    type: Buffer
+    buffer:
+      # Ready floor is deliberately independent of Allocated capacity. Agones
+      # scales Allocated servers down to zero while preserving this buffer.
+      minReady: 2
+      maxReady: 6
+      bufferSize: 2

deploy/k8s/base/kustomization.yaml

@@ -7,3 +7,4 @@ resources:
   - network-policies.yaml
   - control-plane-deployment.yaml
   - fleet.yaml
+  - fleet-autoscaler.yaml