feat: 新增工作流执行模块

新增流程执行记录的实体、DTO、DAO、控制器和服务层，支持工作流的执行、回调及结果树状列表查询；同时更新服务名称为 ai-agent。

workflow/controller/flow/flow_execution_controller.go

@@ -0,0 +1,26 @@
+package flow
+
+import (
+	flowDto "ai-agent/workflow/model/dto/flow"
+	flowService "ai-agent/workflow/service/flow"
+	"context"
+
+	"gitea.com/red-future/common/beans"
+)
+
+type flowExecution struct{}
+
+var FlowExecution = new(flowExecution)
+
+func (c *flowExecution) Execute(ctx context.Context, req *flowDto.ExecuteReq) (res *flowDto.ExecuteRes, err error) {
+	return flowService.FlowExecutionService.Execute(ctx, req)
+}
+
+func (c *flowExecution) ModelCallback(ctx context.Context, req *flowDto.ModelCallbackReq) (res *beans.ResponseEmpty, err error) {
+	err = flowService.FlowExecutionService.ModelCallback(ctx, req)
+	return
+}
+
+func (c *flowExecution) List(ctx context.Context, req *flowDto.ListFlowExecutionReq) (res *flowDto.ListFlowExecutionTreeRes, err error) {
+	return flowService.FlowExecutionService.List(ctx, req)
+}