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/eq.js

@@ -0,0 +1,37 @@
+/**
+ * Performs a
+ * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
+ * comparison between two values to determine if they are equivalent.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category Lang
+ * @param {*} value The value to compare.
+ * @param {*} other The other value to compare.
+ * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
+ * @example
+ *
+ * var object = { 'a': 1 };
+ * var other = { 'a': 1 };
+ *
+ * _.eq(object, object);
+ * // => true
+ *
+ * _.eq(object, other);
+ * // => false
+ *
+ * _.eq('a', 'a');
+ * // => true
+ *
+ * _.eq('a', Object('a'));
+ * // => false
+ *
+ * _.eq(NaN, NaN);
+ * // => true
+ */
+function eq(value, other) {
+  return value === other || (value !== value && other !== other);
+}
+
+module.exports = eq;