refactor: export API returns JSON with download URL, add FileCacheService

src/main/java/com/gmp/mock/handler/GlobalExceptionHandler.java

@@ -1,6 +1,5 @@
 package com.gmp.mock.handler;
 
-import java.util.Map;
 import java.util.stream.Collectors;
 
 import org.springframework.http.ResponseEntity;
@@ -8,23 +7,24 @@ import org.springframework.web.bind.MethodArgumentNotValidException;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.RestControllerAdvice;
 
+import com.gmp.mock.dto.ApiResponse;
 import com.gmp.mock.service.TemplateNotFoundException;
 
 @RestControllerAdvice
 public class GlobalExceptionHandler {
 
     @ExceptionHandler(MethodArgumentNotValidException.class)
-    public ResponseEntity<Map<String, Object>> handleValidation(MethodArgumentNotValidException ex) {
+    public ResponseEntity<ApiResponse<Void>> handleValidation(MethodArgumentNotValidException ex) {
         String message = ex.getBindingResult().getFieldErrors().stream()
                 .map(e -> e.getDefaultMessage())
                 .collect(Collectors.joining("; "));
         return ResponseEntity.badRequest()
-                .body(Map.of("code", 400, "msg", message));
+                .body(ApiResponse.error(400, message));
     }
 
     @ExceptionHandler(TemplateNotFoundException.class)
-    public ResponseEntity<Map<String, Object>> handleTemplateNotFound(TemplateNotFoundException ex) {
+    public ResponseEntity<ApiResponse<Void>> handleTemplateNotFound(TemplateNotFoundException ex) {
         return ResponseEntity.status(404)
-                .body(Map.of("code", 404, "msg", ex.getMessage()));
+                .body(ApiResponse.error(404, ex.getMessage()));
     }
 }