Make layerId easier to use in non-sketch cases

src/lib/maplibre/zorder.ts

@@ -1,15 +1,20 @@
-import { type Config, map as mapStore } from "$lib/config";
+import { map as mapStore } from "$lib/config";
 import { get } from "svelte/store";
 
 interface LayerProps {
   id: string;
   beforeId: string | undefined;
 }
 
+// Just require the subset of config needed, to make it easier for some callers
+interface ConfigWithZorder {
+  layerZorder: string[];
+}
+
 // Use this helper for every svelte-maplibre layer component. It sets the layer
 // ID, beforeId (for z-ordering between layers), and defaults to only using the
 // top-most layer for hovering/clicking.
-export function layerId<F, S>(cfg: Config<F, S>, layerId: string): LayerProps {
+export function layerId(cfg: ConfigWithZorder, layerId: string): LayerProps {
   return {
     id: layerId,
     beforeId: getBeforeId(cfg, layerId),
@@ -20,8 +25,8 @@ export function layerId<F, S>(cfg: Config<F, S>, layerId: string): LayerProps {
 // Svelte component initialization order being unpredictable, callers might add
 // layers in any order. Use beforeId to guarantee the layers wind up in an
 // explicitly defined order.
-function getBeforeId<F, S>(
-  cfg: Config<F, S>,
+function getBeforeId(
+  cfg: ConfigWithZorder,
   layerId: string,
 ): string | undefined {
   let map = get(mapStore);