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/2020/SetFunctionName.js

@@ -0,0 +1,40 @@
+'use strict';
+
+var hasOwn = require('hasown');
+
+var $TypeError = require('es-errors/type');
+
+var getSymbolDescription = require('get-symbol-description');
+
+var DefinePropertyOrThrow = require('./DefinePropertyOrThrow');
+var IsExtensible = require('./IsExtensible');
+
+// https://262.ecma-international.org/6.0/#sec-setfunctionname
+
+module.exports = function SetFunctionName(F, name) {
+	if (typeof F !== 'function') {
+		throw new $TypeError('Assertion failed: `F` must be a function');
+	}
+	if (!IsExtensible(F) || hasOwn(F, 'name')) {
+		throw new $TypeError('Assertion failed: `F` must be extensible, and must not have a `name` own property');
+	}
+	if (typeof name !== 'symbol' && typeof name !== 'string') {
+		throw new $TypeError('Assertion failed: `name` must be a Symbol or a String');
+	}
+	if (typeof name === 'symbol') {
+		var description = getSymbolDescription(name);
+		// eslint-disable-next-line no-param-reassign
+		name = typeof description === 'undefined' ? '' : '[' + description + ']';
+	}
+	if (arguments.length > 2) {
+		var prefix = arguments[2];
+		// eslint-disable-next-line no-param-reassign
+		name = prefix + ' ' + name;
+	}
+	return DefinePropertyOrThrow(F, 'name', {
+		'[[Value]]': name,
+		'[[Writable]]': false,
+		'[[Enumerable]]': false,
+		'[[Configurable]]': true
+	});
+};