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/2022/tables/typed-array-objects.js

@@ -0,0 +1,36 @@
+'use strict';
+
+// https://262.ecma-international.org/11.0/#table-the-typedarray-constructors
+
+module.exports = {
+	__proto__: null,
+	name: {
+		__proto__: null,
+		$Int8Array: 'Int8',
+		$Uint8Array: 'Uint8',
+		$Uint8ClampedArray: 'Uint8C',
+		$Int16Array: 'Int16',
+		$Uint16Array: 'Uint16',
+		$Int32Array: 'Int32',
+		$Uint32Array: 'Uint32',
+		$BigInt64Array: 'BigInt64',
+		$BigUint64Array: 'BigUint64',
+		$Float32Array: 'Float32',
+		$Float64Array: 'Float64'
+	},
+	size: {
+		__proto__: null,
+		$Int8: 1,
+		$Uint8: 1,
+		$Uint8C: 1,
+		$Int16: 2,
+		$Uint16: 2,
+		$Int32: 4,
+		$Uint32: 4,
+		$BigInt64: 8,
+		$BigUint64: 8,
+		$Float32: 4,
+		$Float64: 8
+	},
+	choices: '"Int8", "Uint8", "Uint8C", "Int16", "Uint16", "Int32", "Uint32", "BigInt64", "BigUint64", "Float32", or "Float64"'
+};