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/deburr.js

@@ -0,0 +1,45 @@
+var deburrLetter = require('./_deburrLetter'),
+    toString = require('./toString');
+
+/** Used to match Latin Unicode letters (excluding mathematical operators). */
+var reLatin = /[\xc0-\xd6\xd8-\xf6\xf8-\xff\u0100-\u017f]/g;
+
+/** Used to compose unicode character classes. */
+var rsComboMarksRange = '\\u0300-\\u036f',
+    reComboHalfMarksRange = '\\ufe20-\\ufe2f',
+    rsComboSymbolsRange = '\\u20d0-\\u20ff',
+    rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange;
+
+/** Used to compose unicode capture groups. */
+var rsCombo = '[' + rsComboRange + ']';
+
+/**
+ * Used to match [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks) and
+ * [combining diacritical marks for symbols](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks_for_Symbols).
+ */
+var reComboMark = RegExp(rsCombo, 'g');
+
+/**
+ * Deburrs `string` by converting
+ * [Latin-1 Supplement](https://en.wikipedia.org/wiki/Latin-1_Supplement_(Unicode_block)#Character_table)
+ * and [Latin Extended-A](https://en.wikipedia.org/wiki/Latin_Extended-A)
+ * letters to basic Latin letters and removing
+ * [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks).
+ *
+ * @static
+ * @memberOf _
+ * @since 3.0.0
+ * @category String
+ * @param {string} [string=''] The string to deburr.
+ * @returns {string} Returns the deburred string.
+ * @example
+ *
+ * _.deburr('déjà vu');
+ * // => 'deja vu'
+ */
+function deburr(string) {
+  string = toString(string);
+  return string && string.replace(reLatin, deburrLetter).replace(reComboMark, '');
+}
+
+module.exports = deburr;