refactor: improve question service entity types and security config

- Change Question entity time fields from Date to LocalDateTime for Java 8+ time API consistency
- Add auto-fill annotation for updateTime field in Question and QuestionSubmit entities
- Simplify Serializable import in QuestionQueryRequestDTO
- Temporarily set SecurityConfiguration to permit all requests for development
- Remove generated .flattened-pom.xml build artifacts from version control

Co-Authored-By: Claude <noreply@anthropic.com>

aioj-backend-common/aioj-backend-common-mybatis/src/test/java/cn/meowrain/aioj/generator/CodeGenerator.java

@@ -46,9 +46,9 @@ public class CodeGenerator {
     /** 父包名 */
     private static final String PARENT_PACKAGE = "cn.meowrain.aioj.backend";
     /** 模块名 (如: userservice, questionservice) */
-    private static final String MODULE_NAME = "fileservice";
+    private static final String MODULE_NAME = "question.service";
     /** 要生成的表名 (多个表用逗号分隔) */
-    private static final String[] TABLE_NAMES = {"attachment"};
+    private static final String[] TABLE_NAMES = {"question"};
     /** 表前缀 (生成时会去掉前缀) */
     private static final String[] TABLE_PREFIX = {""};
 
@@ -101,8 +101,8 @@ public class CodeGenerator {
                         .idType(IdType.ASSIGN_ID)  // 雪花算法ID
                         .addTableFills(new Column("create_time", FieldFill.INSERT))
                         .addTableFills(new Column("update_time", FieldFill.INSERT_UPDATE))
-                        .logicDeleteColumnName("del_flag")
-                        .logicDeletePropertyName("delFlag")
+                        .logicDeleteColumnName("is_delete")
+                        .logicDeletePropertyName("isDelete")
                         // Mapper 策略
                         .mapperBuilder()
                         .enableBaseResultMap()