fix: extract nested properties from list API responses

Backend returns { plans: [...] } and { members: [...] } for list
endpoints, not direct arrays. Update listPlans() and listMembers()
to extract the nested property from the response.

Fixes:
- TypeError: t.map is not a function on Plans page
- TypeError: l is not iterable on Members page

src/lib/api/facility-admin.ts

@@ -114,7 +114,12 @@ export async function listPlans(
       headers: { 'Content-Type': 'application/json' },
     });
 
-    return handleApiResponse<MembershipPlan[]>(response);
+    const result = await handleApiResponse<any>(response);
+    // Backend returns { plans: [...] } - extract the plans array
+    if (result.success && result.data.plans) {
+      return { success: true, data: result.data.plans };
+    }
+    return result as FacilityAdminApiResult<MembershipPlan[]>;
   } catch (error) {
     return {
       success: false,
@@ -406,7 +411,12 @@ export async function listMembers(
       headers: { 'Content-Type': 'application/json' },
     });
 
-    return handleApiResponse<FacilityMember[]>(response);
+    const result = await handleApiResponse<any>(response);
+    // Backend returns { members: [...] } - extract the members array
+    if (result.success && result.data.members) {
+      return { success: true, data: result.data.members };
+    }
+    return result as FacilityAdminApiResult<FacilityMember[]>;
   } catch (error) {
     return {
       success: false,