Cleanup after svelte-maplibre refactor

[dabreegster]

• Plumb paint properties in InterventionColorSelector instead of setting directly
• Rethink behavior of multiple overlapping features, especially for the LPA layer
• Rethink the route and polygon .ts tools managing sources/layers, and maybe cleanup the old maplibre util functions
• Stop using the gjScheme store in the browse page
• Use svelte-maplibre for the critical entry draggable marker (only geocode on dragend)
• Use svelte-maplibre for the line measurement tool
• Update dev docs (some HMR guidance refers to old methods)
• Consider new UX patterns, like showing a popup both on hover, and then making it "sticky" when clicked
• Revisit interactiveMapLayersEnabled and make sure browse layers are inactive when other tools are active. Try an invisible layer that covers everything?
• Improve critical clustering (see below)
• Changing schemes in the browse page doesn't update Filters immediately, or has odd behavior when a text filter is in-place
• Layer z-ordering may not be consistent (related to beforeId upgrades dimfeld/svelte-maplibre#25 ?)

Critical clustering has changed and feels a bit more buggy to me. I can't figure out why yet; svelte-maplibre seems to plumb through the cluster options just fine. Before:

After:

Note some of the text counts don't show up.