fix(n+1): 批量查询替代循环单查

- IsAdminBootstrapRequired: userRepo.GetByID 循环 → GetByIDs 批量
- AssignRoles: roleRepo.GetByID 循环 → GetByIDs 批量
- 在 userRepositoryInterface 补充 GetByIDs 方法签名

internal/api/middleware/operation_log.go

@@ -88,6 +88,11 @@ func (m *OperationLogMiddleware) Record() gin.HandlerFunc {
 		}
 
 		go func(entry *domain.OperationLog) {
+			defer func() {
+				if r := recover(); r != nil {
+					// PERF-07: panic recover 保护，防止操作日志写入异常导致进程崩溃
+				}
+			}()
 			ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
 			defer cancel()
 			_ = m.repo.Create(ctx, entry)