Add payments-mcp (Layer 3 MCP surface), single-route pattern from the start

list-payments/get-payment (all 5 roles) and create-payment (admin
only — matches PaymentPermission's actual write-access logic, not
guessed). One KongRoute for GET/POST/DELETE, one ai-mcp-proxy
binding — avoids the duplicate-tool-name bug found and fixed on
customers-mcp (STATUS.md section 18), built correctly here instead
of repeating the two-route mistake.

Keycloak (local): mcp-payments-audience client scope + mcp-payments
resource client, attached to librechat as an optional scope, no
dedicated protocol mappers on the client itself.

kong/kustomization.yaml

@@ -12,3 +12,12 @@ resources:
   - rest/audit-log-body-capture.yaml
   - rest/audit-log-body-capture-bindings.yaml
   - rest/pluginbindings.yaml
+  - mcp/service.yaml
+  - mcp/routes.yaml
+  - mcp/consumergroups.yaml
+  - mcp/ai-mcp-proxy.yaml
+  - mcp/openid-connect.yaml
+  - mcp/audit-log.yaml
+  - mcp/audit-log-body-capture.yaml
+  - mcp/audit-log-body-capture-bindings.yaml
+  - mcp/pluginbindings.yaml