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/2019/NumberToRawBytes.js

@@ -0,0 +1,59 @@
+'use strict';
+
+var $TypeError = require('es-errors/type');
+
+var hasOwnProperty = require('./HasOwnProperty');
+var ToInt16 = require('./ToInt16');
+var ToInt32 = require('./ToInt32');
+var ToInt8 = require('./ToInt8');
+var ToUint16 = require('./ToUint16');
+var ToUint32 = require('./ToUint32');
+var ToUint8 = require('./ToUint8');
+var ToUint8Clamp = require('./ToUint8Clamp');
+
+var valueToFloat32Bytes = require('../helpers/valueToFloat32Bytes');
+var valueToFloat64Bytes = require('../helpers/valueToFloat64Bytes');
+var integerToNBytes = require('../helpers/integerToNBytes');
+
+var tableTAO = require('./tables/typed-array-objects');
+
+// https://262.ecma-international.org/8.0/#table-50
+
+var TypeToAO = {
+	__proto__: null,
+	$Int8: ToInt8,
+	$Uint8: ToUint8,
+	$Uint8C: ToUint8Clamp,
+	$Int16: ToInt16,
+	$Uint16: ToUint16,
+	$Int32: ToInt32,
+	$Uint32: ToUint32
+};
+
+// https://262.ecma-international.org/8.0/#sec-numbertorawbytes
+
+module.exports = function NumberToRawBytes(type, value, isLittleEndian) {
+	if (typeof type !== 'string' || !hasOwnProperty(tableTAO.size, '$' + type)) {
+		throw new $TypeError('Assertion failed: `type` must be a TypedArray element type');
+	}
+	if (typeof value !== 'number') {
+		throw new $TypeError('Assertion failed: `value` must be a Number');
+	}
+	if (typeof isLittleEndian !== 'boolean') {
+		throw new $TypeError('Assertion failed: `isLittleEndian` must be a Boolean');
+	}
+
+	if (type === 'Float32') { // step 1
+		return valueToFloat32Bytes(value, isLittleEndian);
+	} else if (type === 'Float64') { // step 2
+		return valueToFloat64Bytes(value, isLittleEndian);
+	} // step 3
+
+	var n = tableTAO.size['$' + type]; // step 3.a
+
+	var convOp = TypeToAO['$' + type]; // step 3.b
+
+	var intValue = convOp(value); // step 3.c
+
+	return integerToNBytes(intValue, n, isLittleEndian); // step 3.d, 3.e, 4
+};