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/_hasUnicode.js

@@ -0,0 +1,26 @@
+/** Used to compose unicode character classes. */
+var rsAstralRange = '\\ud800-\\udfff',
+    rsComboMarksRange = '\\u0300-\\u036f',
+    reComboHalfMarksRange = '\\ufe20-\\ufe2f',
+    rsComboSymbolsRange = '\\u20d0-\\u20ff',
+    rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange,
+    rsVarRange = '\\ufe0e\\ufe0f';
+
+/** Used to compose unicode capture groups. */
+var rsZWJ = '\\u200d';
+
+/** Used to detect strings with [zero-width joiners or code points from the astral planes](http://eev.ee/blog/2015/09/12/dark-corners-of-unicode/). */
+var reHasUnicode = RegExp('[' + rsZWJ + rsAstralRange  + rsComboRange + rsVarRange + ']');
+
+/**
+ * Checks if `string` contains Unicode symbols.
+ *
+ * @private
+ * @param {string} string The string to inspect.
+ * @returns {boolean} Returns `true` if a symbol is found, else `false`.
+ */
+function hasUnicode(string) {
+  return reHasUnicode.test(string);
+}
+
+module.exports = hasUnicode;