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/lodash/defer.js

@@ -0,0 +1,26 @@
+var baseDelay = require('./_baseDelay'),
+    baseRest = require('./_baseRest');
+
+/**
+ * Defers invoking the `func` until the current call stack has cleared. Any
+ * additional arguments are provided to `func` when it's invoked.
+ *
+ * @static
+ * @memberOf _
+ * @since 0.1.0
+ * @category Function
+ * @param {Function} func The function to defer.
+ * @param {...*} [args] The arguments to invoke `func` with.
+ * @returns {number} Returns the timer id.
+ * @example
+ *
+ * _.defer(function(text) {
+ *   console.log(text);
+ * }, 'deferred');
+ * // => Logs 'deferred' after one millisecond.
+ */
+var defer = baseRest(function(func, args) {
+  return baseDelay(func, 1, args);
+});
+
+module.exports = defer;