feat: 添加管理员权限检查功能和Maven打包配置优化

主要更新：

1. 新增管理员权限检查功能
   - 添加 UserRoleEnum 枚举类统一管理用户角色（USER, ADMIN, BAN）
   - 改进 ContextHolderUtils.isAdmin() 方法，支持不区分大小写的角色比较
   - 更新 UserServiceImpl 使用枚举常量代替硬编码字符串
   - 新增管理员权限使用指南文档 (docs/admin-permission-guide.md)

2. 修复Maven打包配置
   - 配置根POM的spring-boot-maven-plugin默认跳过repackage
   - 为所有服务模块启用repackage，确保可以打包为可执行JAR
   - 修复公共库模块打包失败的问题
   - 涉及服务：gateway, auth, user-service, question-service, file-service, blog-service, upms-biz, ai-service

3. 更新项目文档
   - README.md：添加详细的打包说明、首次克隆准备工作、服务启动顺序等
   - CLAUDE.md：更新项目架构说明和开发指南

4. 重构题目服务责任链结构
   - 将责任链类按功能分类到 question/ 和 submit/ 子目录
   - 新增 QuestionSubmitJudgeInfoEnum 和相关查询功能
   - 改进题目提交服务的实现

5. 其他改进
   - 添加 Feign Token 中继拦截器
   - 更新 AsyncConfig 配置
   - 优化 Jackson 和 Security 配置

aioj-backend-common/aioj-backend-common-feign/src/main/java/cn/meowrain/aioj/backend/framework/feign/FeignAutoConfiguration.java

@@ -1,8 +1,16 @@
 package cn.meowrain.aioj.backend.framework.feign;
 
+import cn.meowrain.aioj.backend.framework.feign.interceptor.TokenRelayRequestInterceptor;
+import feign.RequestInterceptor;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
+import org.springframework.context.annotation.Bean;
 
 @AutoConfiguration
 public class FeignAutoConfiguration {
 
+	@Bean
+	public RequestInterceptor tokenRelayRequestInterceptor() {
+		return new TokenRelayRequestInterceptor();
+	}
+
 }

aioj-backend-common/aioj-backend-common-feign/src/main/java/cn/meowrain/aioj/backend/framework/feign/interceptor/TokenRelayRequestInterceptor.java

@@ -0,0 +1,60 @@
+package cn.meowrain.aioj.backend.framework.feign.interceptor;
+
+import cn.meowrain.aioj.backend.framework.feign.annotation.NoToken;
+import feign.RequestInterceptor;
+import feign.RequestTemplate;
+import jakarta.servlet.http.HttpServletRequest;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.util.StringUtils;
+import org.springframework.web.context.request.RequestContextHolder;
+import org.springframework.web.context.request.ServletRequestAttributes;
+
+import java.lang.reflect.Method;
+
+/**
+ * Feign 调用时透传 Authorization 头
+ */
+public class TokenRelayRequestInterceptor implements RequestInterceptor {
+
+	private static final String HEADER_NAME = "Authorization";
+	private static final String TOKEN_PREFIX = "Bearer ";
+
+	@Override
+	public void apply(RequestTemplate template) {
+		if (isNoToken(template) || template.headers().containsKey(HEADER_NAME)) {
+			return;
+		}
+
+		String authorization = resolveAuthorization();
+		if (StringUtils.hasText(authorization)) {
+			template.header(HEADER_NAME, authorization);
+		}
+	}
+
+	private boolean isNoToken(RequestTemplate template) {
+		if (template.methodMetadata() == null) {
+			return false;
+		}
+		Method method = template.methodMetadata().method();
+		return method != null && (method.isAnnotationPresent(NoToken.class)
+				|| method.getDeclaringClass().isAnnotationPresent(NoToken.class));
+	}
+
+	private String resolveAuthorization() {
+		ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
+		if (attributes != null) {
+			HttpServletRequest request = attributes.getRequest();
+			return request.getHeader(HEADER_NAME);
+		}
+
+		Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
+		if (authentication != null && authentication.getDetails() instanceof String token
+				&& StringUtils.hasText(token)) {
+			return token.startsWith(TOKEN_PREFIX) ? token : TOKEN_PREFIX + token;
+		}
+
+		return null;
+	}
+
+}