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/vaultstaticsecret.yaml

@@ -0,0 +1,34 @@
+---
+apiVersion: secrets.hashicorp.com/v1beta1
+kind: VaultStaticSecret
+metadata:
+  name: postgres-credentials
+  namespace: litellm
+spec:
+  destination:
+    create: true
+    name: postgres-credentials
+    overwrite: true
+  hmacSecretData: true
+  mount: kv
+  path: kubernetes/namespace/litellm/default/postgres-credentials
+  refreshAfter: 5m
+  type: kv-v2
+  vaultAuthRef: default
+---
+apiVersion: secrets.hashicorp.com/v1beta1
+kind: VaultStaticSecret
+metadata:
+  name: litellm-credentials
+  namespace: litellm
+spec:
+  destination:
+    create: true
+    name: litellm-credentials
+    overwrite: true
+  hmacSecretData: true
+  mount: kv
+  path: kubernetes/namespace/litellm/default/litellm-credentials
+  refreshAfter: 5m
+  type: kv-v2
+  vaultAuthRef: default