sync: bring over remaining release/custom-0.1.115 changes

- Extract PublicSettingsInjectionPayload named struct with drift test
- Add channel_monitor_default_interval_seconds to SSR injection
- Add image_output_price to SupportedModelChip
- Simplify AppSidebar buildSelfNavItems (admins see available channels)
- Add gateway WARN logs for 503 no-available-accounts branches
- Wire ChannelMonitorRunner into provideCleanup for graceful shutdown
- Add migrations 130/131 (CC template userid fix + mimicry field cleanup)
- Clean up fork-only features (sora, claude max simulation, client affinity)
- Remove ~320 obsolete i18n keys
- Add codexUsage utility, WechatServiceButton, BulkEditAccountModal
- Tidy go.sum

backend/internal/service/admin_service_bulk_update_test.go

@@ -43,6 +43,16 @@ func (s *accountRepoStubForBulkUpdate) BindGroups(_ context.Context, accountID i
 	return nil
 }
 
+func (s *accountRepoStubForBulkUpdate) ListByGroup(_ context.Context, groupID int64) ([]Account, error) {
+	if err, ok := s.listByGroupErr[groupID]; ok {
+		return nil, err
+	}
+	if rows, ok := s.listByGroupData[groupID]; ok {
+		return rows, nil
+	}
+	return nil, nil
+}
+
 func (s *accountRepoStubForBulkUpdate) GetByIDs(_ context.Context, ids []int64) ([]*Account, error) {
 	s.getByIDsCalled = true
 	s.getByIDsIDs = append([]int64{}, ids...)
@@ -63,16 +73,6 @@ func (s *accountRepoStubForBulkUpdate) GetByID(_ context.Context, id int64) (*Ac
 	return nil, errors.New("account not found")
 }
 
-func (s *accountRepoStubForBulkUpdate) ListByGroup(_ context.Context, groupID int64) ([]Account, error) {
-	if err, ok := s.listByGroupErr[groupID]; ok {
-		return nil, err
-	}
-	if rows, ok := s.listByGroupData[groupID]; ok {
-		return rows, nil
-	}
-	return nil, nil
-}
-
 // TestAdminService_BulkUpdateAccounts_AllSuccessIDs 验证批量更新成功时返回 success_ids/failed_ids。
 func TestAdminService_BulkUpdateAccounts_AllSuccessIDs(t *testing.T) {
 	repo := &accountRepoStubForBulkUpdate{}