feat: 流水线队列引擎 — max_executors并发控制 + Jenkins风格构建队列+取消

backend/internal/api/routes/routes.go

@@ -474,6 +474,9 @@ func Register(r *gin.Engine, db *gorm.DB, log *zap.Logger, cfg *config.Config, c
 			pipelineScoped.POST("/runs/:runId/stop", pipelineHandler.StopPipelineRun)
 			pipelineScoped.POST("/runs/batch-delete", pipelineHandler.BatchDeleteRuns)
 			pipelineScoped.GET("/runs/:runId/log", pipelineHandler.GetRunLog)
+			// 队列管理
+			pipelineScoped.GET("/queue", pipelineHandler.GetPipelineQueue)
+			pipelineScoped.DELETE("/queue/:runId", pipelineHandler.CancelQueueItem)
 			// 成员管理
 			pipelineScoped.GET("/members", pipelineHandler.ListPipelineMembers)
 			pipelineScoped.POST("/members", pipelineHandler.AddPipelineMember)