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/es-abstract/2024/MakeDataViewWithBufferWitnessRecord.js

@@ -0,0 +1,26 @@
+'use strict';
+
+var $TypeError = require('es-errors/type');
+
+var ArrayBufferByteLength = require('./ArrayBufferByteLength');
+var IsDetachedBuffer = require('./IsDetachedBuffer');
+
+var dataViewBuffer = require('data-view-buffer');
+var isDataView = require('is-data-view');
+
+// https://262.ecma-international.org/15.0/#sec-makedataviewwithbufferwitnessrecord
+
+module.exports = function MakeDataViewWithBufferWitnessRecord(obj, order) {
+	if (!isDataView(obj)) {
+		throw new $TypeError('MakeDataViewWithBufferWitnessRecord called with non-DataView');
+	}
+	if (order !== 'SEQ-CST' && order !== 'UNORDERED') {
+		throw new $TypeError('Assertion failed: `order` must be ~SEQ-CST~ or ~UNORDERED~');
+	}
+
+	var buffer = dataViewBuffer(obj); // step 1
+
+	var byteLength = IsDetachedBuffer(buffer) ? 'DETACHED' : ArrayBufferByteLength(buffer, order); // steps 2 - 3
+
+	return { '[[Object]]': obj, '[[CachedBufferByteLength]]': byteLength }; // step 4
+};