feat(admin): migrate core schema to single-pass model

admin/internal/domain/purchase_attempt.go

@@ -0,0 +1,74 @@
+package domain
+
+import (
+	"errors"
+	"time"
+)
+
+var ErrInvalidAttemptTransition = errors.New("invalid purchase attempt status transition")
+
+// AttemptStatus 只描述单趟领取的可恢复执行。真实提交结果独立由唯一围栏记录调和。
+type AttemptStatus string
+
+const (
+	AttemptStatusClaimed   AttemptStatus = "CLAIMED"
+	AttemptStatusOrdering  AttemptStatus = "ORDERING"
+	AttemptStatusFailed    AttemptStatus = "FAILED"
+	AttemptStatusFenced    AttemptStatus = "FENCED"
+	AttemptStatusAbandoned AttemptStatus = "ABANDONED"
+)
+
+// AttemptFailureCode 是服务端可审计的固定失败摘要，不能承载页面正文或其他自由文本。
+type AttemptFailureCode string
+
+const (
+	AttemptFailureAuthorizationExpired AttemptFailureCode = "AUTHORIZATION_EXPIRED"
+	AttemptFailureLeaseLost            AttemptFailureCode = "LEASE_LOST"
+	AttemptFailureGate1Rejected        AttemptFailureCode = "GATE_1_REJECTED"
+	AttemptFailureQuantityMismatch     AttemptFailureCode = "QUANTITY_MISMATCH"
+	AttemptFailureGate2Rejected        AttemptFailureCode = "GATE_2_REJECTED"
+	AttemptFailureGate3Rejected        AttemptFailureCode = "GATE_3_REJECTED"
+	AttemptFailureFenceRejected        AttemptFailureCode = "FENCE_REJECTED"
+	AttemptFailureSafeAborted          AttemptFailureCode = "SAFE_ABORTED"
+)
+
+type PurchaseAttempt struct {
+	ID              string
+	TaskID          string
+	AuthorizationID string
+	ClaimGeneration int
+	Status          AttemptStatus
+	Gate1UnitPrice  *string
+	Gate2UnitPrice  *string
+	QuantityRead    *int
+	ConfirmAmount   *string
+	FailureCode     *AttemptFailureCode
+	StartedAt       time.Time
+	FinishedAt      *time.Time
+}
+
+// CanTransitionTo 只允许围栏前的领取恢复为安全失败；围栏后不再提供回退或重试路径。
+func (status AttemptStatus) CanTransitionTo(next AttemptStatus) bool {
+	_, allowed := attemptTransitions[status][next]
+	return allowed
+}
+
+func TransitionAttempt(current, next AttemptStatus) (AttemptStatus, error) {
+	if !current.CanTransitionTo(next) {
+		return current, ErrInvalidAttemptTransition
+	}
+	return next, nil
+}
+
+var attemptTransitions = map[AttemptStatus]map[AttemptStatus]struct{}{
+	AttemptStatusClaimed: {
+		AttemptStatusOrdering:  {},
+		AttemptStatusFailed:    {},
+		AttemptStatusAbandoned: {},
+	},
+	AttemptStatusOrdering: {
+		AttemptStatusFenced:    {},
+		AttemptStatusFailed:    {},
+		AttemptStatusAbandoned: {},
+	},
+}