fix: replace non-existent TsProxy CRD with ProxyGroup

TsProxy is not a CRD shipped by the Tailscale operator (v1.96.x).
The operator provides: ProxyClass, ProxyGroup, ProxyGroupPolicy,
DNSConfig, Tailnet, Connector, and Recorder.

Replace TsProxy with ProxyGroup (type: ingress) and annotate
rtx6000-brain-service with tailscale.com/proxy-group to expose
the vLLM endpoint via MagicDNS at rtx6000-brain-0.<tailnet>.ts.net:8000.

infrastructure/controllers/base/tailscale/tsproxy-rtx6000.yaml

@@ -1,9 +0,0 @@
-apiVersion: tailscale.com/v1
-kind: TsProxy
-metadata:
-  name: rtx6000-brain
-  namespace: customer1
-spec:
-  serviceName: rtx6000-brain-service
-  servicePort: 8000
-  hostname: rtx6000-brain

infrastructure/gpus/base/vllm-servers/rtx6000-vllm.yaml

@@ -130,6 +130,8 @@ kind: Service
 metadata:
   name: rtx6000-brain-service
   namespace: customer1
+  annotations:
+    tailscale.com/proxy-group: rtx6000-brain
 spec:
   selector:
     app: rtx6000-brain

infrastructure/tailnet/kustomization.yaml

@@ -1,4 +1,4 @@
 apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 resources:
-  - tsproxy-rtx6000.yaml
+  - proxygroup-rtx6000.yaml

infrastructure/tailnet/proxygroup-rtx6000.yaml

@@ -0,0 +1,9 @@
+apiVersion: tailscale.com/v1alpha1
+kind: ProxyGroup
+metadata:
+  name: rtx6000-brain
+spec:
+  type: ingress
+  hostnamePrefix: rtx6000-brain
+  tags:
+    - tag:k8s

infrastructure/tailnet/tsproxy-rtx6000.yaml

@@ -1,9 +0,0 @@
-apiVersion: tailscale.com/v1
-kind: TsProxy
-metadata:
-  name: rtx6000-brain
-  namespace: customer1
-spec:
-  serviceName: rtx6000-brain-service
-  servicePort: 8000
-  hostname: rtx6000-brain