Build sales-api REST + MCP layers (Layer 3), full build in one pass

14 routes: Order (single key, full CRUD + order-details sub-resource)
and Orderdetail (composite key ordernumber+productcode, own
top-level resource, mirrors backend's own URL structure). MCP layer
built with the corrected single-route pattern from the start
(STATUS.md section 18) — 7 tools, list/get read-only for all 5
roles, create-order/create-orderdetail for admin+customer+support
(verified against OrderPermission/OrderScopedPermission.check() —
support gets an unconditional class-level pass, the status-only
restriction is object-level and doesn't apply to create).

Keycloak (local): sales-api-audience + mcp-sales-audience client
scopes, sales-api + mcp-sales resource clients, attached to the
broker and librechat respectively. Deploy key and broker secret
reused/mirrored from catalog-api and the live broker client, same
pattern as customers-api/payments-api.

kong/rest/proxy-cache.yaml

@@ -0,0 +1,16 @@
+apiVersion: configuration.konghq.com/v1
+kind: KongPlugin
+metadata:
+  name: ${NAME}-sales-api-proxy-cache
+  namespace: ${NAMESPACE}
+plugin: proxy-cache-advanced
+config:
+  strategy: memory
+  request_method:
+    - GET
+    - HEAD
+  response_code:
+    - 200
+  content_type:
+    - application/json
+  cache_ttl: 60