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/resources/config.yaml

@@ -0,0 +1,15 @@
+model_list: []
+
+router_settings:
+  redis_host: redis-service
+  redis_port: 6379
+
+general_settings:
+  use_redis_transaction_buffer: true
+
+litellm_settings:
+  cache: true
+  cache_params:
+    type: redis
+    host: redis-service
+    port: 6379