feat: add litellm to new aitooling ArgoCD project (#94)

Deploys LiteLLM proxy with CNPG PostgreSQL (3-instance HA), PgBouncer
pooler, and Redis cache. Introduces a dedicated aitooling AppProject and
ApplicationSet to keep AI tooling services separate from platform infra.

Reviewed-on: #94

apps/base/litellm/ingress.yaml

@@ -0,0 +1,29 @@
+---
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  annotations:
+    kubernetes.io/ingress.class: nginx
+    external-dns.alpha.kubernetes.io/hostname: litellm.k8s.syd1.au.unkin.net
+    external-dns.alpha.kubernetes.io/target: 198.18.200.0
+    cert-manager.io/cluster-issuer: vault-issuer
+    cert-manager.io/common-name: litellm.k8s.syd1.au.unkin.net
+    cert-manager.io/private-key-size: "4096"
+  name: litellm
+  namespace: litellm
+spec:
+  rules:
+    - host: litellm.k8s.syd1.au.unkin.net
+      http:
+        paths:
+          - backend:
+              service:
+                name: litellm
+                port:
+                  number: 4000
+            path: /
+            pathType: Prefix
+  tls:
+    - hosts:
+        - litellm.k8s.syd1.au.unkin.net
+      secretName: litellm-tls