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/hpa.yaml

@@ -0,0 +1,41 @@
+---
+apiVersion: autoscaling/v2
+kind: HorizontalPodAutoscaler
+metadata:
+  name: litellm-hpa
+  namespace: litellm
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: litellm
+  minReplicas: 2
+  maxReplicas: 10
+  metrics:
+    - type: Resource
+      resource:
+        name: cpu
+        target:
+          type: Utilization
+          averageUtilization: 60
+  behavior:
+    scaleUp:
+      stabilizationWindowSeconds: 0
+      selectPolicy: Max
+      policies:
+        - type: Percent
+          value: 100
+          periodSeconds: 30
+        - type: Pods
+          value: 4
+          periodSeconds: 30
+    scaleDown:
+      stabilizationWindowSeconds: 300
+      selectPolicy: Min
+      policies:
+        - type: Percent
+          value: 10
+          periodSeconds: 60
+        - type: Pods
+          value: 2
+          periodSeconds: 60