Diagonal filter followup

A few followups after #98:

- [ ] Reconsider the savefile format; geojson is clunky. `filters_to_gj` has two different uses
- [ ] Can't hover on a diagonal filter in debug mode and get properties popup; just a layer zorder issue?
- [ ] Clicking twice in edit mode zooms in
- [x] ~~Make routing actually respect the Movements built from one-ways, turn restrictions, diagonal filters, etc~~ tracked at #101
- [ ] After routing works, ping the user who was waiting for diagonal filters

查看对角过滤器的代码，它可能位于处理地图编辑或路由的模块中。检查 savefile 格式和 `filters_to_gj` 函数，以了解它的两种用途。检查调试模式 UI 中图层的 z-order 以排查 hover 问题，并调查编辑模式的点击处理以查找缩放 bug。先查看 PR #98 中的更改，了解当前实现。

由索引模型根据 Issue 内容生成。