Add a Home button and fill icon gaps from NPS's newer symbol library

Two things pulled in from github.com/nationalparkservice/npmap5-plugins:

- A "Home" button (public/vendor/npmap-home-button/, NPS's own MapLibre
  control) pinned to the app's CENTER/ZOOM, sitting top-left on the map. Now
  that the URL hash permalink can open the map at any view, "current view"
  and "the default view" aren't the same thing anymore, so a quick way back
  to the default is worth having.

- npmap5-plugins bundles a newer, actively-maintained version of the same
  NPS symbol-library already used for POI_ICONS (confirmed by its
  maintainer to be the designated replacement for the older standalone
  repo: nationalparkservice/npmap5-plugins#4), with a much larger icon
  vocabulary and a simpler CC0 (public domain) license. All 25 icons
  already in use came back byte-identical from the new source, so this
  just repoints their attribution — but it also has icons the old repo
  didn't: `forest` (POI_ICONS) is now the official "wilderness" pictogram
  instead of hand-drawn, and three of the five previously icon-less
  Services/Activities tags (wifi, mobile data coverage, winter/snow
  camping) now have real icons too. Only bakery and vehicle wash still
  have no NPS equivalent.

public/js/map.js

@@ -11,6 +11,7 @@ import { LiveTrackPanelControl } from "/js/livetrack.js";
 import { TrackProfilePanel } from "/js/track_profile.js";
 import { LAYERS_ICON } from "/js/icons.js";
 import { notifySidePanelOpen, onlyOneSidePanelOpen } from "/js/panels.js";
+import HomeButton from "/vendor/npmap-home-button/home-button.esm.js";
 
 const CENTER = [17.1077, 48.1486];
 const ZOOM = 13;
@@ -133,6 +134,13 @@ map.addControl(
   }),
   "bottom-right",
 );
+// homePosition/zoom pinned to the app's own default rather than left to the
+// button's own fallback (current center/zoom at construction) — now that
+// the URL hash can restore any view on load (see the Hash option above),
+// "current view" and "the default view" are no longer the same thing, and
+// a home button that resets to wherever you happened to load the page
+// wouldn't be a home button.
+map.addControl(new HomeButton({ homePosition: CENTER, zoom: ZOOM }), "top-left");
 
 const sidebar = document.getElementById("sidebar");