feat: use hosted default_style.json instead of hardcoded layer styling

[Pbhacks]

Fixes #345

Instead of hardcoding Valhalla layer styles in the app (which will become stale), the app now fetches layer definitions at runtime from the upstream hosted default_style.json in the valhalla repository.

Changes:

• Add fetchValhallaLayers() that fetches from raw.githubusercontent.com/valhalla/valhalla/master/docs/docs/api/tile/default_style.json
• Layer IDs and source references are remapped to match the app conventions
• Fetched layers are cached per session to avoid redundant network requests
• Falls back to hardcoded layers if the remote fetch fails
• Updated valhalla-layers-toggle to use async fetchValhallaLayers()
• Updated tests with full coverage for the new fetch behavior

🛠️ Fixes Issue

Closes #345

📄 Note to reviewers

I have made necessary changes kindly let me know if it is good.

[Copilot]

Pull request overview

This PR replaces hardcoded Valhalla MapLibre layer styling with runtime-fetched layer definitions from Valhalla’s upstream default_style.json, while keeping hardcoded layers as a fallback.

Changes:

• Added fetchValhallaLayers() to fetch and adapt upstream layers, with a session cache and hardcoded fallback.
• Updated ValhallaLayersToggle to asynchronously fetch layers before adding/removing them.
• Extended unit tests to cover the new fetch behavior and async toggle behavior.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
src/components/tiles/valhalla-layers.ts	Adds remote style URL constant, layer adaptation, session cache, and async fetch with fallback to hardcoded layers.
src/components/tiles/valhalla-layers.spec.ts	Adds tests for the default style URL and fetch/fallback behavior.
src/components/tiles/valhalla-layers-toggle.tsx	Switches to async layer fetching and stores fetched layers for later removal.
src/components/tiles/valhalla-layers-toggle.spec.tsx	Mocks fetchValhallaLayers() and updates assertions to wait for async behavior.

Comments suppressed due to low confidence (2)

src/components/tiles/valhalla-layers-toggle.tsx:59

• In the toggle-off branch, the code removes every layer in layersRef.current if it exists on the map, even if that layer pre-existed and was not added by this toggle (note the toggle-on branch skips addLayer when a layer already exists). This can accidentally remove layers owned by other parts of the app if IDs overlap. Track which layer IDs were actually added (e.g., push to a ref/set only when addLayer is called) and only remove those on toggle-off.

      for (const layer of layers) {
        if (!map.getLayer(layer.id)) {
          map.addLayer(layer);
        }
      }
    } else {
      for (const layer of layersRef.current) {
        if (map.getLayer(layer.id)) {
          map.removeLayer(layer.id);
        }
      }

src/components/tiles/valhalla-layers-toggle.tsx:63

• map.removeSource(VALHALLA_SOURCE_ID) is called whenever the toggle is switched off, even if the source already existed before toggling on (the toggle-on branch conditionally calls addSource). This can remove a source that another component expects to remain. Similar to layers, track whether this toggle added the source (e.g., addedSourceRef.current = true only when calling addSource) and only remove it when it was added here.

      if (!map.getSource(VALHALLA_SOURCE_ID)) {
        map.addSource(VALHALLA_SOURCE_ID, getValhallaSourceSpec());
      }
      for (const layer of layers) {
        if (!map.getLayer(layer.id)) {
          map.addLayer(layer);
        }
      }
    } else {
      for (const layer of layersRef.current) {
        if (map.getLayer(layer.id)) {
          map.removeLayer(layer.id);
        }
      }

      if (map.getSource(VALHALLA_SOURCE_ID)) {
        map.removeSource(VALHALLA_SOURCE_ID);
      }

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[nilsnolde]

same here. follow the guidelines. also you can see that @lourduradjou already was asking in #345. it'd be the sensible thing to first claim the issue, but I'll let this slide bcs it's kinda stale after 3 days.

[Pbhacks]

Hi apologies @nilsnolde for not claiming it before, I will keep that in mind in future issues and do accordingly. Thanks for allowing me

[github-actions]

Preview is ready! 🚀 You can view it here: https://valhalla-app-tests.gis-ops.com/361