fix(admin): cash close report uses cash payments only for expected cash

- expectedCash now = openingCash + cash payments (not total sales)
- difference = actualCash - realExpectedCash
- Closes ADMIN-CLOSURES

work/runtime-status.json

@@ -1,9 +1,9 @@
 {
-  "feature_id": null,
-  "stage": "idle",
-  "agent": "leader",
+  "feature_id": "ADMIN-CLOSURES",
+  "stage": "build",
+  "agent": "implementer",
   "action": "",
-  "state": "idle",
+  "state": "running",
   "next_agent": "leader",
   "waiting_for": "Seleccionar una feature pending y actualizar este estado",
   "updated_at": "2026-08-24T14:15:00Z",