fix: 防止重复报名 - 个人项目和集体项目都添加重复检查

- 个人项目：检测到重复报名时返回错误而非更新
- 集体项目：添加重复报名检查
- 新增 /martial/athlete/registered API 用于查询已报名选手

Closes #3

src/main/java/org/springblade/modules/martial/controller/MartialAthleteController.java

@@ -1,5 +1,7 @@
 package org.springblade.modules.martial.controller;
 
+import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
+import java.util.List;
 import com.baomidou.mybatisplus.core.metadata.IPage;
 import com.qiniu.util.Auth;
 import io.swagger.v3.oas.annotations.Operation;
@@ -106,4 +108,25 @@ public class MartialAthleteController extends BladeController {
 		return R.success("状态更新成功");
 	}
 
+	/**
+	 * 获取已报名选手列表（用于检查重复报名）
+	 */
+	@GetMapping("/registered")
+	@Operation(summary = "获取已报名选手", description = "查询指定赛事和项目的已报名选手")
+	public R<List<MartialAthlete>> getRegisteredAthletes(
+			@RequestParam Long competitionId,
+			@RequestParam(required = false) String projectIds) {
+		LambdaQueryWrapper<MartialAthlete> wrapper = new LambdaQueryWrapper<>();
+		wrapper.eq(MartialAthlete::getCompetitionId, competitionId)
+			.eq(MartialAthlete::getIsDeleted, 0)
+			.eq(MartialAthlete::getRegistrationStatus, 1);
+		
+		if (Func.isNotBlank(projectIds)) {
+			wrapper.in(MartialAthlete::getProjectId, Func.toLongList(projectIds));
+		}
+		
+		List<MartialAthlete> list = athleteService.list(wrapper);
+		return R.data(list);
+	}
+
 }

src/main/java/org/springblade/modules/martial/controller/MartialRegistrationOrderController.java

@@ -329,6 +329,19 @@ public class MartialRegistrationOrderController extends BladeController {
 				
 				// Create a record for each project
 				for (Long projectId : projectIds) {
+					// Check if team already registered for this project
+					LambdaQueryWrapper<MartialAthlete> teamCheckWrapper = new LambdaQueryWrapper<>();
+					teamCheckWrapper.eq(MartialAthlete::getCompetitionId, dto.getCompetitionId())
+						.eq(MartialAthlete::getProjectId, projectId)
+						.eq(MartialAthlete::getTeamName, team.getTeamName())
+						.eq(MartialAthlete::getIsDeleted, 0);
+					MartialAthlete existingTeamRecord = athleteService.getOne(teamCheckWrapper, false);
+					
+					if (existingTeamRecord != null) {
+						log.warn("集体重复报名: teamName={}, projectId={}", team.getTeamName(), projectId);
+						return R.fail("集体 " + team.getTeamName() + " 已报名该项目，请勿重复报名");
+					}
+					
 					MartialAthlete teamAthlete = new MartialAthlete();
 					teamAthlete.setOrderId(orderId);
 					teamAthlete.setCompetitionId(dto.getCompetitionId());
@@ -368,13 +381,9 @@ public class MartialRegistrationOrderController extends BladeController {
 					MartialAthlete existingRecord = athleteService.getOne(checkWrapper, false);
 					
 					if (existingRecord != null) {
-						// Update existing record with order info
-						existingRecord.setOrderId(orderId);
-						existingRecord.setRegistrationStatus(1);
-						existingRecord.setUpdateUser(AuthUtil.getUserId());
-						existingRecord.setUpdateTime(new java.util.Date());
-						athleteService.updateById(existingRecord);
-						log.info("更新已存在的选手参赛记录: playerName={}, projectId={}", existingAthlete.getPlayerName(), projectId);
+						// Reject duplicate registration
+						log.warn("选手重复报名: playerName={}, projectId={}", existingAthlete.getPlayerName(), projectId);
+						return R.fail("选手 " + existingAthlete.getPlayerName() + " 已报名该项目，请勿重复报名");
 					} else {
 						// Create new record
 						MartialAthlete newRecord = new MartialAthlete();