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/internal/parallel.js

@@ -0,0 +1,34 @@
+'use strict';
+
+Object.defineProperty(exports, "__esModule", {
+    value: true
+});
+
+var _isArrayLike = require('./isArrayLike.js');
+
+var _isArrayLike2 = _interopRequireDefault(_isArrayLike);
+
+var _wrapAsync = require('./wrapAsync.js');
+
+var _wrapAsync2 = _interopRequireDefault(_wrapAsync);
+
+var _awaitify = require('./awaitify.js');
+
+var _awaitify2 = _interopRequireDefault(_awaitify);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+exports.default = (0, _awaitify2.default)((eachfn, tasks, callback) => {
+    var results = (0, _isArrayLike2.default)(tasks) ? [] : {};
+
+    eachfn(tasks, (task, key, taskCb) => {
+        (0, _wrapAsync2.default)(task)((err, ...result) => {
+            if (result.length < 2) {
+                [result] = result;
+            }
+            results[key] = result;
+            taskCb(err);
+        });
+    }, err => callback(err, results));
+}, 3);
+module.exports = exports.default;