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/2025/UpdateModifiers.js

@@ -0,0 +1,77 @@
+'use strict';
+
+var $TypeError = require('es-errors/type');
+var callBound = require('call-bound');
+var hasOwn = require('hasown');
+
+var isRegExpRecord = require('../helpers/records/regexp-record');
+
+var $charAt = callBound('String.prototype.charAt');
+
+// https://262.ecma-international.org/16.0/#sec-updatemodifiers
+
+module.exports = function UpdateModifiers(rer, add, remove) {
+	if (!isRegExpRecord(rer)) {
+		throw new $TypeError('Assertion failed: `rer` must be a RegExp Record');
+	}
+	if (typeof add !== 'string') {
+		throw new $TypeError('Assertion failed: `add` must be a string');
+	}
+	if (typeof remove !== 'string') {
+		throw new $TypeError('Assertion failed: `remove` must be a string');
+	}
+
+	// 1. Assert: add and remove have no elements in common.
+	var adds = { __proto__: null };
+	var removes = { __proto__: null };
+	for (var i = 0; i < add.length; i++) {
+		var toAdd = $charAt(add, i);
+		adds[toAdd] = true;
+	}
+	for (var j = 0; j < remove.length; j++) {
+		var toRemove = $charAt(remove, j);
+		if (hasOwn(adds, toRemove)) {
+			throw new $TypeError('Assertion failed: `add` and `remove` have elements in common');
+		}
+		removes[toRemove] = true;
+	}
+
+	var ignoreCase = rer['[[IgnoreCase]]']; // step 2
+
+	var multiline = rer['[[Multiline]]']; // step 3
+
+	var dotAll = rer['[[DotAll]]']; // step 4
+
+	var unicode = rer['[[Unicode]]']; // step 5
+
+	var unicodeSets = rer['[[UnicodeSets]]']; // step 6
+
+	var capturingGroupsCount = rer['[[CapturingGroupsCount]]']; // step 7
+
+	if (hasOwn(removes, 'i')) {
+		ignoreCase = false; // step 8
+	} else if (hasOwn(adds, 'i')) {
+		ignoreCase = true; // step 9
+	}
+
+	if (hasOwn(removes, 'm')) {
+		multiline = false; // step 10
+	} else if (hasOwn(adds, 'm')) {
+		multiline = true; // step 11
+	}
+
+	if (hasOwn(removes, 's')) {
+		dotAll = false; // step 12
+	} else if (hasOwn(adds, 's')) {
+		dotAll = true; // step 13
+	}
+
+	return {
+		'[[IgnoreCase]]': !!ignoreCase,
+		'[[Multiline]]': !!multiline,
+		'[[DotAll]]': !!dotAll,
+		'[[Unicode]]': !!unicode,
+		'[[UnicodeSets]]': !!unicodeSets,
+		'[[CapturingGroupsCount]]': capturingGroupsCount
+	}; // step 14
+};