fix: websearch features_config cleanup and pricing rules validation

- Fix web_search_emulation toggle: explicitly write false for disabled
  platforms instead of leaving stale true from cloned features_config
- Extract validatePricingEntries from validateChannelConfig for reuse
- Validate account_stats_pricing_rules[].pricing in both Create and
  Update paths (negative prices, bad intervals, missing per_request price)

backend/internal/service/channel_service.go

@@ -566,13 +566,19 @@ func ReplaceModelInBody(body []byte, newModel string) []byte {
 // validateChannelConfig 校验渠道的定价和映射配置（冲突检测 + 区间校验 + 计费模式校验）。
 // Create 和 Update 共用此函数，避免重复。
 func validateChannelConfig(pricing []ChannelModelPricing, mapping map[string]map[string]string) error {
-	if err := validateNoConflictingModels(pricing); err != nil {
+	if err := validatePricingEntries(pricing); err != nil {
 		return err
 	}
-	if err := validatePricingIntervals(pricing); err != nil {
+	return validateNoConflictingMappings(mapping)
+}
+
+// validatePricingEntries 校验定价条目（冲突检测 + 区间校验 + 计费模式校验），
+// 同时用于主渠道定价和 account_stats_pricing_rules 的内部定价。
+func validatePricingEntries(pricing []ChannelModelPricing) error {
+	if err := validateNoConflictingModels(pricing); err != nil {
 		return err
 	}
-	if err := validateNoConflictingMappings(mapping); err != nil {
+	if err := validatePricingIntervals(pricing); err != nil {
 		return err
 	}
 	return validatePricingBillingMode(pricing)
@@ -684,6 +690,11 @@ func (s *ChannelService) Create(ctx context.Context, input *CreateChannelInput)
 	if err := validateChannelConfig(channel.ModelPricing, channel.ModelMapping); err != nil {
 		return nil, err
 	}
+	for i, rule := range channel.AccountStatsPricingRules {
+		if err := validatePricingEntries(rule.Pricing); err != nil {
+			return nil, fmt.Errorf("account stats pricing rule #%d: %w", i+1, err)
+		}
+	}
 
 	if err := s.repo.Create(ctx, channel); err != nil {
 		return nil, fmt.Errorf("create channel: %w", err)
@@ -712,6 +723,11 @@ func (s *ChannelService) Update(ctx context.Context, id int64, input *UpdateChan
 	if err := validateChannelConfig(channel.ModelPricing, channel.ModelMapping); err != nil {
 		return nil, err
 	}
+	for i, rule := range channel.AccountStatsPricingRules {
+		if err := validatePricingEntries(rule.Pricing); err != nil {
+			return nil, fmt.Errorf("account stats pricing rule #%d: %w", i+1, err)
+		}
+	}
 
 	oldGroupIDs := s.getOldGroupIDs(ctx, id)
 

frontend/src/views/admin/ChannelsView.vue

@@ -1032,15 +1032,19 @@ function formToAPI(): { group_ids: number[], model_pricing: ChannelModelPricing[
   }
 
   // Collect web_search_emulation (only anthropic platform supports it)
+  // Always write the key so that disabling in the UI correctly sets platform to false,
+  // rather than leaving a stale true value from the cloned features_config.
   const wsEmulation: Record<string, boolean> = {}
   for (const section of form.platforms) {
     if (!section.enabled) continue
-    if (section.web_search_emulation && section.platform === 'anthropic') {
-      wsEmulation[section.platform] = true
+    if (section.platform === 'anthropic') {
+      wsEmulation[section.platform] = !!section.web_search_emulation
     }
   }
   if (Object.keys(wsEmulation).length > 0) {
     featuresConfig.web_search_emulation = wsEmulation
+  } else {
+    delete featuresConfig.web_search_emulation
   }
 
   return { group_ids, model_pricing, model_mapping, features_config: featuresConfig }