Add progressive web app companion for cross-platform access

Vite + TypeScript PWA that mirrors the Android app's core features:
- Pre-processed shelter data (build-time UTM33N→WGS84 conversion)
- Leaflet map with shelter markers, user location, and offline tiles
- Canvas compass arrow (ported from DirectionArrowView.kt)
- IndexedDB shelter cache with 7-day staleness check
- Service worker with CacheFirst tiles and precached app shell
- i18n for en, nb, nn (ported from Android strings.xml)
- iOS/Android compass handling with low-pass filter
- Respects user map interaction (no auto-snap on pan/zoom)
- Build revision cache-breaker for reliable SW updates

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pwa/node_modules/@babel/runtime/helpers/esm/get.js

@@ -0,0 +1,11 @@
+import superPropBase from "./superPropBase.js";
+function _get() {
+  return _get = "undefined" != typeof Reflect && Reflect.get ? Reflect.get.bind() : function (e, t, r) {
+    var p = superPropBase(e, t);
+    if (p) {
+      var n = Object.getOwnPropertyDescriptor(p, t);
+      return n.get ? n.get.call(arguments.length < 3 ? e : r) : n.value;
+    }
+  }, _get.apply(null, arguments);
+}
+export { _get as default };