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/importDeferProxy.js

@@ -0,0 +1,27 @@
+function _importDeferProxy(e) {
+  var t = null,
+    constValue = function constValue(e) {
+      return function () {
+        return e;
+      };
+    },
+    proxy = function proxy(r) {
+      return function (n, o, f) {
+        return null === t && (t = e()), r(t, o, f);
+      };
+    };
+  return new Proxy({}, {
+    defineProperty: constValue(!1),
+    deleteProperty: constValue(!1),
+    get: proxy(Reflect.get),
+    getOwnPropertyDescriptor: proxy(Reflect.getOwnPropertyDescriptor),
+    getPrototypeOf: constValue(null),
+    isExtensible: constValue(!1),
+    has: proxy(Reflect.has),
+    ownKeys: proxy(Reflect.ownKeys),
+    preventExtensions: constValue(!0),
+    set: constValue(!1),
+    setPrototypeOf: constValue(!1)
+  });
+}
+export { _importDeferProxy as default };