Edit turn restrictions: leftovers

- [ ] Check results near https://www.openstreetmap.org/way/158782224. The maptiler basemap seems wrong here; there's no oneway.
- [ ] Arrows too small at https://www.openstreetmap.org/node/5113845431
- [x] Depends on #101
- [ ] Decide what turn restrictions to visualize, especially when they clash with oneways

Test cases:
- a "blackhole" of oneways pointing at each other
- a simple example https://www.openstreetmap.org/relation/3880112

Followups from #180:

- [ ] Account for one-ways in get_turn_restriction_targets` (See [here](https://github.com/a-b-street/ltn/pull/180#discussion_r1976002464) -- maybe not -- maybe instead highlight redundant or conflicting cases)
- [ ] bug: Click on a road to make a TR from it, click map, blue focus remains
- [ ] bug: Click to delete a TR, preview line remains
- [ ] improve toolbar width responsiveness
- [ ] make pico tooltips on the toolbar buttons cover the map
- [ ] Maybe rotate the TR icon in the popup when showing what'll be created
- [ ] `turn_restrictions` could be a BTreeMap, and `travel_flows` ought to be a Vec

The issue involves editing turn restrictions in the LTN web tool. Start by examining the code around `get_turn_restriction_targets` and the `turn_restrictions` data structure, likely in a file like `src/turn_restrictions.rs`. Test the listed OpenStreetMap way and node URLs in the tool to see the visual bugs. Check PR #180 for context on one-way handling and UI issues like the blue focus remaining. 'Done' means fixing the visual bugs and implementing the decisions about turn restriction visualization.

Written by the indexing model from the issue text.