Allow cross-store staff selection

backend/src/main/java/com/petshop/backend/controller/DropdownController.java

@@ -156,13 +156,20 @@ public class DropdownController {
         );
     }
 
-    @GetMapping("/stores/{storeId}/employees")
+    @GetMapping({"/stores/{storeId}/employees", "/employees"})
     @PreAuthorize("hasAnyRole('CUSTOMER', 'STAFF', 'ADMIN')")
-    public ResponseEntity<List<DropdownOption>> getStoreEmployees(@PathVariable Long storeId) {
+    public ResponseEntity<List<DropdownOption>> getStoreEmployees(@PathVariable(required = false) Long storeId) {
+        List<EmployeeStore> employees;
+        if (storeId == null || storeId == 0) {
+            employees = employeeStoreRepository.findActiveAllOrderByEmployeeEmployeeIdAsc();
+        } else {
+            employees = employeeStoreRepository.findActiveByStoreStoreIdOrderByEmployeeEmployeeIdAsc(storeId);
+        }
         return ResponseEntity.ok(
-                employeeStoreRepository.findActiveByStoreStoreIdOrderByEmployeeEmployeeIdAsc(storeId).stream()
+                employees.stream()
                         .filter(this::isAssignableEmployee)
                         .map(this::toEmployeeOption)
+                        .distinct()
                         .collect(Collectors.toList())
         );
     }

backend/src/main/java/com/petshop/backend/repository/EmployeeStoreRepository.java

@@ -15,4 +15,7 @@ public interface EmployeeStoreRepository extends JpaRepository<EmployeeStore, Em
 
     @Query("SELECT es FROM EmployeeStore es WHERE es.store.storeId = :storeId AND es.employee.isActive = true ORDER BY es.employee.employeeId ASC")
     List<EmployeeStore> findActiveByStoreStoreIdOrderByEmployeeEmployeeIdAsc(@Param("storeId") Long storeId);
+
+    @Query("SELECT es FROM EmployeeStore es WHERE es.employee.isActive = true ORDER BY es.employee.employeeId ASC")
+    List<EmployeeStore> findActiveAllOrderByEmployeeEmployeeIdAsc();
 }