fix: drawer open/close updates UI immediately without refresh

- Return null instead of throwing on 404 for drawer current query
- Sync drawer session ID to null when drawer closes
- Await query invalidation before closing dialog
- Fix unused approvedBy lint error

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/admin/src/api/pos.ts

@@ -121,7 +121,13 @@ export function transactionOptions(id: string | null) {
 export function currentDrawerOptions(locationId: string | null) {
   return queryOptions({
     queryKey: posKeys.drawer(locationId ?? ''),
-    queryFn: () => api.get<DrawerSession>('/v1/drawer/current', { locationId }),
+    queryFn: async (): Promise<DrawerSession | null> => {
+      try {
+        return await api.get<DrawerSession>('/v1/drawer/current', { locationId })
+      } catch {
+        return null // 404 = no open drawer
+      }
+    },
     enabled: !!locationId,
     retry: false,
   })