fix(调度): 完善粘性会话清理与账号调度刷新

- Update/BulkUpdate 按不可调度字段触发缓存刷新
- GatewayCache 支持多前缀会话键清理
- 模型路由与混合调度优化粘性会话处理
- 补充调度与缓存相关测试覆盖

backend/internal/repository/scheduler_snapshot_outbox_integration_test.go

@@ -19,7 +19,7 @@ func TestSchedulerSnapshotOutboxReplay(t *testing.T) {
 
 	_, _ = integrationDB.ExecContext(ctx, "TRUNCATE scheduler_outbox")
 
-	accountRepo := newAccountRepositoryWithSQL(client, integrationDB)
+	accountRepo := newAccountRepositoryWithSQL(client, integrationDB, nil)
 	outboxRepo := NewSchedulerOutboxRepository(integrationDB)
 	cache := NewSchedulerCache(rdb)