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/async/forEachSeries.js

@@ -0,0 +1,44 @@
+'use strict';
+
+Object.defineProperty(exports, "__esModule", {
+    value: true
+});
+
+var _eachLimit = require('./eachLimit.js');
+
+var _eachLimit2 = _interopRequireDefault(_eachLimit);
+
+var _awaitify = require('./internal/awaitify.js');
+
+var _awaitify2 = _interopRequireDefault(_awaitify);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+/**
+ * The same as [`each`]{@link module:Collections.each} but runs only a single async operation at a time.
+ *
+ * Note, that unlike [`each`]{@link module:Collections.each}, this function applies iteratee to each item
+ * in series and therefore the iteratee functions will complete in order.
+
+ * @name eachSeries
+ * @static
+ * @memberOf module:Collections
+ * @method
+ * @see [async.each]{@link module:Collections.each}
+ * @alias forEachSeries
+ * @category Collection
+ * @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
+ * @param {AsyncFunction} iteratee - An async function to apply to each
+ * item in `coll`.
+ * The array index is not passed to the iteratee.
+ * If you need the index, use `eachOfSeries`.
+ * Invoked with (item, callback).
+ * @param {Function} [callback] - A callback which is called when all
+ * `iteratee` functions have finished, or an error occurs. Invoked with (err).
+ * @returns {Promise} a promise, if a callback is omitted
+ */
+function eachSeries(coll, iteratee, callback) {
+    return (0, _eachLimit2.default)(coll, 1, iteratee, callback);
+}
+exports.default = (0, _awaitify2.default)(eachSeries, 3);
+module.exports = exports.default;