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/consts/flow/flow_template_status.go

@@ -0,0 +1,26 @@
+package flow
+
+import "github.com/gogf/gf/v2/util/gconv"
+
+var (
+	FlowTemplateStatusDisable = newFlowTemplateStatus(gconv.PtrInt8(0), "disable")
+	FlowTemplateStatusEnable  = newFlowTemplateStatus(gconv.PtrInt8(1), "enable")
+)
+
+type FlowTemplateStatus *int8
+
+type flowTemplateStatus struct {
+	code FlowTemplateStatus
+	desc string
+}
+
+func (s flowTemplateStatus) Code() FlowTemplateStatus {
+	return s.code
+}
+func (s flowTemplateStatus) Desc() string {
+	return s.desc
+}
+
+func newFlowTemplateStatus(code FlowTemplateStatus, desc string) flowTemplateStatus {
+	return flowTemplateStatus{code: code, desc: desc}
+}