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/2018/AsyncIteratorClose.js

@@ -0,0 +1,64 @@
+'use strict';
+
+var GetIntrinsic = require('get-intrinsic');
+
+var $SyntaxError = require('es-errors/syntax');
+var $TypeError = require('es-errors/type');
+var isObject = require('es-object-atoms/isObject');
+var $Promise = GetIntrinsic('%Promise%', true);
+
+var Call = require('./Call');
+var CompletionRecord = require('./CompletionRecord');
+var GetMethod = require('./GetMethod');
+
+var isIteratorRecord = require('../helpers/records/iterator-record-2023');
+
+var callBound = require('call-bound');
+
+var $then = callBound('Promise.prototype.then', true);
+
+// https://262.ecma-international.org/9.0/#sec-asynciteratorclose
+
+module.exports = function AsyncIteratorClose(iteratorRecord, completion) {
+	if (!isIteratorRecord(iteratorRecord)) {
+		throw new $TypeError('Assertion failed: `iteratorRecord` must be an Iterator Record'); // step 1
+	}
+
+	if (!(completion instanceof CompletionRecord)) {
+		throw new $TypeError('Assertion failed: completion is not a Completion Record instance'); // step 2
+	}
+
+	if (!$then) {
+		throw new $SyntaxError('This environment does not support Promises.');
+	}
+
+	var iterator = iteratorRecord['[[Iterator]]']; // step 3
+
+	return new $Promise(function (resolve) {
+		var ret = GetMethod(iterator, 'return'); // step 4
+
+		if (typeof ret === 'undefined') {
+			resolve(completion); // step 5
+		} else {
+			resolve($then(
+				new $Promise(function (resolve2) {
+					// process.exit(42);
+					resolve2(Call(ret, iterator, [])); // step 6
+				}),
+				function (innerResult) {
+					if (!isObject(innerResult)) {
+						throw new $TypeError('`innerResult` must be an Object'); // step 10
+					}
+					return completion;
+				},
+				function (e) {
+					if (completion.type() === 'throw') {
+						completion['?'](); // step 8
+					} else {
+						throw e; // step 9
+					}
+				}
+			));
+		}
+	});
+};