Migrate map basemap to MapLibre GL Leaflet

[birkskyum]

Proposed change

Replace the map's Leaflet raster tile layer with @maplibre/maplibre-gl-leaflet and the OpenFreeMap Liberty vector style.

This is an incremental migration: Leaflet remains responsible for the map API, entity markers, clustering, paths, and drawing controls, while MapLibre GL JS renders the basemap. This limits the scope of the change and provides a path toward a future native MapLibre implementation.

MapLibre GL JS v6 is ESM-only and requires explicit worker handling when bundled. This PR therefore:

• Adds MapLibre GL JS 6 and the MapLibre GL Leaflet bridge.
• Uses the OpenFreeMap Liberty vector style.
• Configures a same-origin MapLibre worker URL.
• Copies both maplibre-gl-worker.mjs and its required maplibre-gl-shared.mjs sibling into the frontend static assets.
• Includes the MapLibre stylesheet in the map shadow root.
• Updates Rspack handling so ESM-only dependencies resolve correctly.
• Keeps existing Leaflet map behavior and tests intact.

Screenshots

Before: CARTO raster basemap

After: OpenFreeMap Liberty vector basemap

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: Map shows API KEY REQUIRED overlay #53800
• This PR is related to issue or discussion: N/A
• Link to documentation pull request: N/A
• Link to developer documentation pull request: N/A
• Link to backend pull request: N/A
• MapLibre GL JS v6 migration guide: https://maplibre.org/maplibre-gl-js/docs/guides/v5-to-v6-migration-guide/
• OpenFreeMap integration guide: https://openfreemap.org/quick_start/

Validation performed:

• Map component tests pass.
• Type checking passes.
• ESLint, Prettier, and the production dependency license check pass.
• The modern production frontend build completes successfully.
• A browser smoke test confirmed that the Liberty style and its vector source load, MapLibre uses WebGL2, the self-hosted worker modules load, attribution is shown, and Leaflet markers remain visible.

Checklist

• I understand the code I am submitting and can explain how it works.
• The code change is tested and works locally.
• There is no commented out code in this PR.
• I have followed the perfect PR recommendations
• Any generated code has been carefully reviewed for correctness and compliance with project standards.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

To help with the load of incoming pull requests:

• I have reviewed two other open pull requests in this repository.

[home-assistant]

Hi @birkskyum

It seems you haven't yet signed a CLA. Please do so here.

Once you do that we will be able to review and accept this pull request.

Thanks!

[home-assistant]

Please take a look at the requested changes, and use the Ready for review button when you are done, thanks 👍

Learn more about our pull request process.

[bramkragten]

Duplicate of #53816?

[birkskyum]

Yeah, actually! Great work @bramkragten !

[bramkragten]

Thanks for your PR, will take the pieces out that are actually better than mine ;-)