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/_cloneBuffer.js

@@ -0,0 +1,35 @@
+var root = require('./_root');
+
+/** Detect free variable `exports`. */
+var freeExports = typeof exports == 'object' && exports && !exports.nodeType && exports;
+
+/** Detect free variable `module`. */
+var freeModule = freeExports && typeof module == 'object' && module && !module.nodeType && module;
+
+/** Detect the popular CommonJS extension `module.exports`. */
+var moduleExports = freeModule && freeModule.exports === freeExports;
+
+/** Built-in value references. */
+var Buffer = moduleExports ? root.Buffer : undefined,
+    allocUnsafe = Buffer ? Buffer.allocUnsafe : undefined;
+
+/**
+ * Creates a clone of  `buffer`.
+ *
+ * @private
+ * @param {Buffer} buffer The buffer to clone.
+ * @param {boolean} [isDeep] Specify a deep clone.
+ * @returns {Buffer} Returns the cloned buffer.
+ */
+function cloneBuffer(buffer, isDeep) {
+  if (isDeep) {
+    return buffer.slice();
+  }
+  var length = buffer.length,
+      result = allocUnsafe ? allocUnsafe(length) : new buffer.constructor(length);
+
+  buffer.copy(result);
+  return result;
+}
+
+module.exports = cloneBuffer;