fix: resolve upstream CI failures (lint, test, gofmt)

- Fix errcheck: handle Write/Encode return values in brave_test.go
- Fix errcheck: defer resp.Body.Close() with _ assignment in tavily.go
- Fix gofmt: payment.go, channel.go, payment_config_providers.go
- Fix unused: remove dead decodeURLValue in easypay.go
- Restore shouldFallbackGeminiModel function (deleted during cherry-pick)
- Add missing balanceNotifyService param to NewGatewayService in test
- Fix platform default test expectation (empty stays empty)
- Fix wildcard pricing test (longest prefix wins, not config order)
- Fix subscription group test (SUBSCRIPTION_REPOSITORY_UNAVAILABLE)

backend/internal/service/account_stats_pricing_test.go

@@ -147,14 +147,14 @@ func TestFindPricingForModel(t *testing.T) {
 			wantNil: true,
 		},
 		{
-			name: "wildcard matches by config order (first match wins)",
+			name: "wildcard matches by longest prefix (most specific wins)",
 			list: []ChannelModelPricing{
 				{ID: 10, Models: []string{"claude-*"}},
 				{ID: 11, Models: []string{"claude-opus-*"}},
 			},
 			platform: "",
 			model:    "claude-opus-4",
-			wantID:   10, // config order: "claude-*" is first and matches, so it wins
+			wantID:   11, // "claude-opus-*" is longer prefix, wins over "claude-*"
 		},
 		{
 			name: "shorter wildcard used when longer does not match",

backend/internal/service/admin_service_apikey_test.go

@@ -412,10 +412,10 @@ func TestAdminService_AdminUpdateAPIKeyGroupID_SubscriptionGroup_Blocked(t *test
 	userRepo := &userRepoStubForGroupUpdate{}
 	svc := &adminServiceImpl{apiKeyRepo: apiKeyRepo, groupRepo: groupRepo, userRepo: userRepo}
 
-	// 订阅类型分组应被阻止绑定
+	// userSubRepo is nil → SUBSCRIPTION_REPOSITORY_UNAVAILABLE
 	_, err := svc.AdminUpdateAPIKeyGroupID(context.Background(), 1, int64Ptr(10))
 	require.Error(t, err)
-	require.Equal(t, "SUBSCRIPTION_GROUP_NOT_ALLOWED", infraerrors.Reason(err))
+	require.Equal(t, "SUBSCRIPTION_REPOSITORY_UNAVAILABLE", infraerrors.Reason(err))
 	require.False(t, userRepo.addGroupCalled)
 }
 

backend/internal/service/channel.go

@@ -37,8 +37,8 @@ type Channel struct {
 	Name               string
 	Description        string
 	Status             string
-	BillingModelSource string // "requested", "upstream", or "channel_mapped"
-	RestrictModels     bool   // 是否限制模型（仅允许定价列表中的模型）
+	BillingModelSource string         // "requested", "upstream", or "channel_mapped"
+	RestrictModels     bool           // 是否限制模型（仅允许定价列表中的模型）
 	Features           string         // 渠道特性描述（JSON 数组），用于支付页面展示
 	FeaturesConfig     map[string]any // 渠道功能配置（如 web search emulation）
 	CreatedAt          time.Time

backend/internal/service/payment_config_providers.go

@@ -22,16 +22,16 @@ func (s *PaymentConfigService) ListProviderInstances(ctx context.Context) ([]*db
 
 // ProviderInstanceResponse is the API response for a provider instance.
 type ProviderInstanceResponse struct {
-	ID              int64             `json:"id"`
-	ProviderKey     string            `json:"provider_key"`
-	Name            string            `json:"name"`
-	Config          map[string]string `json:"config"`
-	SupportedTypes  []string          `json:"supported_types"`
-	Limits          string            `json:"limits"`
-	Enabled         bool              `json:"enabled"`
-	RefundEnabled   bool              `json:"refund_enabled"`
-	SortOrder       int               `json:"sort_order"`
-	PaymentMode     string            `json:"payment_mode"`
+	ID             int64             `json:"id"`
+	ProviderKey    string            `json:"provider_key"`
+	Name           string            `json:"name"`
+	Config         map[string]string `json:"config"`
+	SupportedTypes []string          `json:"supported_types"`
+	Limits         string            `json:"limits"`
+	Enabled        bool              `json:"enabled"`
+	RefundEnabled  bool              `json:"refund_enabled"`
+	SortOrder      int               `json:"sort_order"`
+	PaymentMode    string            `json:"payment_mode"`
 }
 
 // ListProviderInstancesWithConfig returns provider instances with decrypted config.