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/get-own-enumerable-property-symbols/lib/index.d.ts

@@ -0,0 +1,2 @@
+declare const _default: (object: object) => symbol[];
+export default _default;

pwa/node_modules/get-own-enumerable-property-symbols/lib/index.js

@@ -0,0 +1,6 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.default = (object) => Object
+    .getOwnPropertySymbols(object)
+    .filter((keySymbol) => Object.prototype.propertyIsEnumerable.call(object, keySymbol));
+//# sourceMappingURL=index.js.map

pwa/node_modules/get-own-enumerable-property-symbols/lib/index.js.map

@@ -0,0 +1 @@
+{"version":3,"file":"index.js","sourceRoot":"","sources":["../src/index.ts"],"names":[],"mappings":";;AAAA,kBAAe,CAAC,MAAc,EAAY,EAAE,CAAC,MAAM;KAChD,qBAAqB,CAAC,MAAM,CAAC;KAC7B,MAAM,CAAC,CAAC,SAAS,EAAW,EAAE,CAAC,MAAM,CAAC,SAAS,CAAC,oBAAoB,CAAC,IAAI,CAAC,MAAM,EAAE,SAAS,CAAC,CAAC,CAAA"}