feat: Excel batch registration (equipment + employees)

backend/src/main/java/com/srsystem/dto/BatchResult.java

@@ -0,0 +1,28 @@
+package com.srsystem.dto;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public record BatchResult<T>(
+    int totalCount,
+    int successCount,
+    int failCount,
+    List<Failure> failures,
+    List<T> data
+) {
+    public static <T> BatchResult<T> ok(List<T> data) {
+        return new BatchResult<>(data.size(), data.size(), 0, List.of(), data);
+    }
+
+    public static <T> BatchResult<T> partial(List<T> successData, List<Failure> failures) {
+        return new BatchResult<>(
+            successData.size() + failures.size(),
+            successData.size(),
+            failures.size(),
+            failures,
+            successData
+        );
+    }
+
+    public record Failure(int row, String reason) {}
+}