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/dunder-proto/get.js

@@ -0,0 +1,30 @@
+'use strict';
+
+var callBind = require('call-bind-apply-helpers');
+var gOPD = require('gopd');
+
+var hasProtoAccessor;
+try {
+	// eslint-disable-next-line no-extra-parens, no-proto
+	hasProtoAccessor = /** @type {{ __proto__?: typeof Array.prototype }} */ ([]).__proto__ === Array.prototype;
+} catch (e) {
+	if (!e || typeof e !== 'object' || !('code' in e) || e.code !== 'ERR_PROTO_ACCESS') {
+		throw e;
+	}
+}
+
+// eslint-disable-next-line no-extra-parens
+var desc = !!hasProtoAccessor && gOPD && gOPD(Object.prototype, /** @type {keyof typeof Object.prototype} */ ('__proto__'));
+
+var $Object = Object;
+var $getPrototypeOf = $Object.getPrototypeOf;
+
+/** @type {import('./get')} */
+module.exports = desc && typeof desc.get === 'function'
+	? callBind([desc.get])
+	: typeof $getPrototypeOf === 'function'
+		? /** @type {import('./get')} */ function getDunder(value) {
+			// eslint-disable-next-line eqeqeq
+			return $getPrototypeOf(value == null ? value : $Object(value));
+		}
+		: false;