feat(ECR-009): Ops-D order filters, plan display prices, refund status

LOOP-RUN-002 sample: admin order multi-filter, membership display
price catalog, read-only refund_status. No real payment or RBAC.

Co-authored-by: Cursor <cursoragent@cursor.com>

proto/openapi.yaml

@@ -135,7 +135,37 @@ paths:
   /api/v1/admin/orders:
     get:
       tags: [admin]
-      summary: List orders
+      summary: List orders (Ops-D filters)
+      parameters:
+        - in: query
+          name: status
+          schema: { type: string }
+        - in: query
+          name: kind
+          schema: { type: string }
+        - in: query
+          name: from
+          schema: { type: string, format: date }
+        - in: query
+          name: to
+          schema: { type: string, format: date }
+        - in: query
+          name: user_id
+          schema: { type: string, format: uuid }
+      responses:
+        '200':
+          description: OK (includes refund_status)
+
+  /api/v1/admin/membership/plan-prices:
+    get:
+      tags: [admin]
+      summary: List membership display prices
+      responses:
+        '200':
+          description: OK
+    put:
+      tags: [admin]
+      summary: Upsert membership display prices
       responses:
         '200':
           description: OK