feat: establish Orbit models, migrations and development baseline

pulse/model/state.go

@@ -0,0 +1,57 @@
+package model
+
+// TaskState 表示任务状态，与执行尝试状态独立；任务终态不重新打开。
+type TaskState string
+
+const (
+	TaskWaiting     TaskState = "WAITING"      // 等待派发、延时或退避到期。
+	TaskLeased      TaskState = "LEASED"       // 已领取但尚未获得开始授权。
+	TaskRunning     TaskState = "RUNNING"      // 已授权处理器开始执行。
+	TaskNeedsReview TaskState = "NEEDS_REVIEW" // 结果未知或需要人工核查。
+	TaskSucceeded   TaskState = "SUCCEEDED"    // 业务处理器成功结果已保存。
+	TaskFailed      TaskState = "FAILED"       // 已知失败且不再继续执行。
+	TaskCancelled   TaskState = "CANCELLED"    // 取消已确认，不能理解为业务回滚。
+)
+
+func (s TaskState) Terminal() bool {
+	return s == TaskSucceeded || s == TaskFailed || s == TaskCancelled
+}
+
+// CanTransitionTo 只检查状态图，不能代替数据库事务中的权限、版本、租约、
+// 暂停门控、副作用证据和重试预算校验。
+func (s TaskState) CanTransitionTo(next TaskState) bool {
+	switch s {
+	case TaskWaiting:
+		return next == TaskLeased || next == TaskCancelled || next == TaskFailed
+	case TaskLeased:
+		return next == TaskRunning || next == TaskWaiting || next == TaskCancelled || next == TaskFailed
+	case TaskRunning:
+		return next == TaskSucceeded || next == TaskWaiting || next == TaskFailed || next == TaskNeedsReview || next == TaskCancelled
+	case TaskNeedsReview:
+		return next == TaskSucceeded || next == TaskFailed
+	default:
+		return false
+	}
+}
+
+type AttemptState string
+
+const (
+	AttemptLeased    AttemptState = "LEASED"
+	AttemptRunning   AttemptState = "RUNNING"
+	AttemptSucceeded AttemptState = "SUCCEEDED"
+	AttemptFailed    AttemptState = "FAILED"
+	AttemptCancelled AttemptState = "CANCELLED"
+	AttemptExpired   AttemptState = "EXPIRED"
+	AttemptUnknown   AttemptState = "UNKNOWN"
+)
+
+// RecoverySafety 表示恢复安全等级，空值或未知值默认需要核查。
+type RecoverySafety string
+
+const (
+	RecoveryIdempotent    RecoverySafety = "IDEMPOTENT"     // 接入方明确保证可幂等恢复。
+	RecoveryReconcileOnly RecoverySafety = "RECONCILE_ONLY" // 恢复前必须查询结果或人工核查。
+)
+
+func (s RecoverySafety) CanRecoverAutomatically() bool { return s == RecoveryIdempotent }