refactor: flatten dto entity and mapper packages

src/main/java/com/label/dto/LoginResponse.java

@@ -0,0 +1,29 @@
+package com.label.dto;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+/**
+ * 登录成功响应体。
+ */
+@Data
+@AllArgsConstructor
+@Schema(description = "登录响应")
+public class LoginResponse {
+    /** Bearer Token（UUID v4），后续请求放入 Authorization 头 */
+    @Schema(description = "Bearer Token", example = "550e8400-e29b-41d4-a716-446655440000")
+    private String token;
+    /** 用户主键 */
+    @Schema(description = "用户主键")
+    private Long userId;
+    /** 登录用户名 */
+    @Schema(description = "登录用户名")
+    private String username;
+    /** 角色：UPLOADER / ANNOTATOR / REVIEWER / ADMIN */
+    @Schema(description = "角色", example = "ADMIN")
+    private String role;
+    /** Token 有效期（秒） */
+    @Schema(description = "Token 有效期（秒）", example = "7200")
+    private Long expiresIn;
+}