修复(#128): 按规则类型决定促销资格，让 InactiveUser/Campaign 对老用户生效

此前 calculatePurchasePrice 把 allowPromo 绑死在 orderType == 1，导致只要用户
有任何过往付费订阅（含已过期），就会被 paidSubscriptionQuery 路由为续费
（orderType=2），跳过所有促销评估。后果：

  - InactiveUser 召回促销永远无法触发（其目标人群恰好就是有过期订阅的用户）
  - Campaign 全员活动对老用户 / 升级加购场景完全失效
  - 套餐列表（loadSubscribePromoMap）直接调 EvaluatePromo 不感知 orderType，
    可能显示促销价但下单时却拿到原价

修复方式：把 isFirstPurchase 下放给 EvaluatePromo，由规则类型决定 gating：

  - NewUser    要求 isFirstPurchase=true（保留首购语义）
  - InactiveUser 由规则自身的"上次订阅过期 N 月以上"条件判定
  - Campaign   时间窗内对任意用户生效

新增 common.HasPaidSubscription 助手，套餐列表与下单走同一份 isFirstPurchase
判定，确保展示价与实际下单价口径一致。

测试：补充 EvaluatePromo / calculatePurchasePrice 的 NewUser 屏蔽 + Campaign
放开用例；更新 loadSubscribePromoMap 测试覆盖新增 HasPaidSubscription 查询。

注：renewalLogic.go 仍未接入促销（属于方向 B 的彻底统一，本次未涵盖）。

internal/logic/public/order/promoPricing.go

@@ -27,7 +27,7 @@ func calculatePurchasePrice(
 	quantity int64,
 	discounts []types.SubscribeDiscount,
 	eligibleForDiscount bool,
-	allowPromo bool,
+	isFirstPurchase bool,
 ) (*orderPriceResult, error) {
 	originalPrice := unitPrice * quantity
 	result := &orderPriceResult{
@@ -35,21 +35,19 @@ func calculatePurchasePrice(
 		PayableBase:   originalPrice,
 	}
 
-	if allowPromo {
-		promoResult, err := commonLogic.EvaluatePromo(ctx, svcCtx, userID, subscribeID, quantity)
-		if err != nil {
-			return nil, err
-		}
-		if promoResult != nil && promoResult.Eligible && promoResult.PromoPrice < originalPrice {
-			result.PayableBase = promoResult.PromoPrice
-			result.PromoRuleId = promoResult.RuleID
-			result.PromoDiscount = originalPrice - result.PayableBase
-			result.PromoPrice = promoResult.PromoPrice
-			if result.PromoDiscount < 0 {
-				result.PromoDiscount = 0
-			}
-			return result, nil
+	promoResult, err := commonLogic.EvaluatePromo(ctx, svcCtx, userID, subscribeID, quantity, isFirstPurchase)
+	if err != nil {
+		return nil, err
+	}
+	if promoResult != nil && promoResult.Eligible && promoResult.PromoPrice < originalPrice {
+		result.PayableBase = promoResult.PromoPrice
+		result.PromoRuleId = promoResult.RuleID
+		result.PromoDiscount = originalPrice - result.PayableBase
+		result.PromoPrice = promoResult.PromoPrice
+		if result.PromoDiscount < 0 {
+			result.PromoDiscount = 0
 		}
+		return result, nil
 	}
 
 	discount := float64(1)

internal/logic/public/order/promoPricing_test.go

@@ -221,3 +221,79 @@ func TestCalculatePurchasePricePassesQuantityToPromoEvaluation(t *testing.T) {
 		t.Fatalf("PromoRuleId = %d, want 11", result.PromoRuleId)
 	}
 }
+
+func TestCalculatePurchasePriceCampaignAppliesToReturningUsers(t *testing.T) {
+	model := &fakePromoModel{rules: []*promo.RuleWithPrice{
+		{
+			Rule: promo.Rule{
+				Id:      12,
+				Name:    "campaign",
+				Type:    promo.RuleTypeCampaign,
+				Enabled: true,
+			},
+			PromoPrice: 400,
+		},
+	}}
+	svcCtx := &svc.ServiceContext{DB: &gorm.DB{}, PromoModel: model}
+
+	// isFirstPurchase=false simulates a returning user routed to renewal; the
+	// Campaign promo must still apply because it has no first-purchase gate.
+	result, err := calculatePurchasePrice(
+		context.Background(),
+		svcCtx,
+		42,
+		2,
+		1000,
+		1,
+		nil,
+		false,
+		false,
+	)
+	if err != nil {
+		t.Fatalf("calculatePurchasePrice returned error: %v", err)
+	}
+	if result.PromoRuleId != 12 {
+		t.Fatalf("PromoRuleId = %d, want 12 (campaign should apply to returning users)", result.PromoRuleId)
+	}
+	if result.PayableBase != 400 {
+		t.Fatalf("PayableBase = %d, want 400", result.PayableBase)
+	}
+}
+
+func TestCalculatePurchasePriceNewUserGatedByFirstPurchase(t *testing.T) {
+	model := &fakePromoModel{rules: []*promo.RuleWithPrice{
+		{
+			Rule: promo.Rule{
+				Id:      13,
+				Name:    "new user",
+				Type:    promo.RuleTypeNewUser,
+				Enabled: true,
+				Params:  `{"window_hours": 72}`,
+			},
+			PromoPrice: 200,
+		},
+	}}
+	svcCtx := &svc.ServiceContext{DB: &gorm.DB{}, PromoModel: model}
+
+	// isFirstPurchase=false → NewUser rule must be skipped, regular discount applies.
+	result, err := calculatePurchasePrice(
+		context.Background(),
+		svcCtx,
+		42,
+		2,
+		1000,
+		1,
+		[]types.SubscribeDiscount{{Quantity: 1, Discount: 90}},
+		true,
+		false,
+	)
+	if err != nil {
+		t.Fatalf("calculatePurchasePrice returned error: %v", err)
+	}
+	if result.PromoRuleId != 0 || result.PromoDiscount != 0 {
+		t.Fatalf("promo fields = (%d, %d), want (0, 0) when isFirstPurchase=false", result.PromoRuleId, result.PromoDiscount)
+	}
+	if result.PayableBase != 900 {
+		t.Fatalf("PayableBase = %d, want 900 (regular 90%% discount)", result.PayableBase)
+	}
+}

internal/logic/public/subscribe/promo.go

@@ -42,12 +42,19 @@ func loadSubscribePromoMap(ctx context.Context, svcCtx *svc.ServiceContext, subs
 
 	userInfo, _ := ctx.Value(constant.CtxKeyUser).(*user.User)
 	userID := int64(0)
+	isFirstPurchase := true
 	if userInfo != nil {
 		entitlement, err := commonLogic.ResolveEntitlementUser(ctx, svcCtx.DB, userInfo.Id)
 		if err != nil {
 			return nil, err
 		}
 		userID = entitlement.EffectiveUserID
+
+		hasPaid, err := commonLogic.HasPaidSubscription(ctx, svcCtx.DB, userID)
+		if err != nil {
+			return nil, err
+		}
+		isFirstPurchase = !hasPaid
 	}
 
 	candidates, err := querySubscribePromoCandidates(ctx, svcCtx, subscribeIDs, userInfo != nil)
@@ -68,7 +75,7 @@ func loadSubscribePromoMap(ctx context.Context, svcCtx *svc.ServiceContext, subs
 		if _, exists := result[candidate.SubscribeId][candidate.Quantity]; exists {
 			continue
 		}
-		promoResult, err := commonLogic.EvaluatePromo(ctx, svcCtx, userID, candidate.SubscribeId, candidate.Quantity)
+		promoResult, err := commonLogic.EvaluatePromo(ctx, svcCtx, userID, candidate.SubscribeId, candidate.Quantity, isFirstPurchase)
 		if err != nil {
 			return nil, err
 		}

internal/logic/public/subscribe/promo_test.go

@@ -105,6 +105,9 @@ func TestLoadSubscribePromoMapUsesFamilyOwnerForInactivePromo(t *testing.T) {
 		WithArgs(memberUserID, user.FamilyMemberActive, 1).
 		WillReturnRows(sqlmock.NewRows([]string{"role", "family_status", "owner_user_id"}).
 			AddRow(user.FamilyRoleMember, user.FamilyStatusActive, ownerUserID))
+	mock.ExpectQuery("SELECT count(*) FROM `user_subscribe`").
+		WithArgs(ownerUserID, 1).
+		WillReturnRows(sqlmock.NewRows([]string{"count"}).AddRow(0))
 	mock.ExpectQuery("FROM subscribe_promo AS sp").
 		WillReturnRows(sqlmock.NewRows([]string{
 			"subscribe_id", "quantity", "rule_name", "rule_type", "promo_price", "params", "start_time", "end_time",