feat: 新增用户端配置获取和批量更新接口

主要修改:
1. 在SystemConfigController中新增获取用户端配置的接口。
2. 实现批量更新系统配置的接口，支持根据配置键进行更新。
3. 增强SystemConfigService，添加用户端相关配置的获取方法及配置值验证逻辑。

技术细节:
- 新增的接口提升了系统配置管理的灵活性，支持批量操作和用户端配置的动态获取。

src/main/java/com/gameplatform/server/controller/admin/SystemConfigController.java

@@ -5,6 +5,7 @@ import com.gameplatform.server.model.entity.admin.SystemConfig;
 import com.gameplatform.server.model.dto.admin.SystemConfigRequest;
 import com.gameplatform.server.model.dto.admin.SystemConfigResponse;
 import com.gameplatform.server.model.dto.admin.SystemConfigConverter;
+import com.gameplatform.server.model.dto.admin.BatchSystemConfigRequest;
 import com.gameplatform.server.service.admin.SystemConfigService;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.tags.Tag;
@@ -13,6 +14,7 @@ import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
 import java.util.List;
+import java.util.ArrayList;
 
 @RestController
 @RequestMapping("/api/admin/config")
@@ -117,4 +119,93 @@ public class SystemConfigController {
             public final String qrPathTemplate = systemConfigService.getQrPathTemplate();
         });
     }
+    
+    @GetMapping("/user/config")
+    @Operation(summary = "获取用户端配置", description = "获取用户端相关配置")
+    public ResponseEntity<Object> getUserConfig() {
+        return ResponseEntity.ok(new Object() {
+            public final Integer qrExpireSeconds = systemConfigService.getUserQrExpireSeconds();
+            public final Integer refreshWaitSeconds = systemConfigService.getUserRefreshWaitSeconds();
+            public final Integer linkExpireHours = systemConfigService.getUserLinkExpireHours();
+            public final String assetsBaseUrl = systemConfigService.getUserAssetsBaseUrl();
+        });
+    }
+    
+    @PostMapping("/batch")
+    @Operation(summary = "批量更新配置", description = "批量更新系统配置，支持根据配置键更新")
+    public ResponseEntity<Object> batchUpdateConfigs(@RequestBody BatchSystemConfigRequest request) {
+        if (request.getConfigs() == null || request.getConfigs().isEmpty()) {
+            return ResponseEntity.badRequest().body(new Object() {
+                public final boolean success = false;
+                public final String message = "配置列表不能为空";
+            });
+        }
+        
+        List<SystemConfig> configs = new ArrayList<>();
+        List<String> validationErrors = new ArrayList<>();
+        
+        for (BatchSystemConfigRequest.SystemConfigUpdateItem item : request.getConfigs()) {
+            // 验证配置值
+            if (item.getConfigType() != null && item.getConfigValue() != null) {
+                if (!systemConfigService.validateConfigValue(item.getConfigType(), item.getConfigValue())) {
+                    validationErrors.add("配置键 " + item.getConfigKey() + " 的值格式不正确");
+                    continue;
+                }
+            }
+            
+            SystemConfig config = new SystemConfig();
+            config.setConfigKey(item.getConfigKey());
+            config.setConfigValue(item.getConfigValue());
+            config.setConfigType(item.getConfigType());
+            config.setDescription(item.getDescription());
+            configs.add(config);
+        }
+        
+        if (!validationErrors.isEmpty()) {
+            return ResponseEntity.badRequest().body(new Object() {
+                public final boolean success = false;
+                public final String message = "配置验证失败";
+                public final List<String> errors = validationErrors;
+            });
+        }
+        
+        boolean success = systemConfigService.updateConfigs(configs);
+        final boolean finalSuccess = success;
+        final int finalUpdatedCount = configs.size();
+        
+        return ResponseEntity.ok(new Object() {
+            public final boolean success = finalSuccess;
+            public final String message = finalSuccess ? "批量更新成功" : "批量更新失败";
+            public final int updatedCount = finalUpdatedCount;
+        });
+    }
+    
+    @PutMapping("/key/{configKey}")
+    @Operation(summary = "根据键更新配置值", description = "根据配置键快速更新配置值")
+    public ResponseEntity<Object> updateConfigByKey(
+            @PathVariable String configKey, 
+            @RequestBody String configValue) {
+        
+        // 先获取现有配置以验证类型
+        SystemConfig existingConfig = systemConfigService.getConfigByKey(configKey);
+        if (existingConfig == null) {
+            return ResponseEntity.notFound().build();
+        }
+        
+        // 验证配置值格式
+        if (!systemConfigService.validateConfigValue(existingConfig.getConfigType(), configValue)) {
+            return ResponseEntity.badRequest().body(new Object() {
+                public final boolean success = false;
+                public final String message = "配置值格式不正确，期望类型: " + existingConfig.getConfigType();
+            });
+        }
+        
+        boolean success = systemConfigService.updateConfigValueByKey(configKey, configValue);
+        final boolean finalSuccess = success;
+        
+        return ResponseEntity.ok(new Object() {
+            public final boolean success = finalSuccess;
+            public final String message = finalSuccess ? "更新成功" : "更新失败";
+        });
+    }
 }