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/_createCtor.js

@@ -0,0 +1,37 @@
+var baseCreate = require('./_baseCreate'),
+    isObject = require('./isObject');
+
+/**
+ * Creates a function that produces an instance of `Ctor` regardless of
+ * whether it was invoked as part of a `new` expression or by `call` or `apply`.
+ *
+ * @private
+ * @param {Function} Ctor The constructor to wrap.
+ * @returns {Function} Returns the new wrapped function.
+ */
+function createCtor(Ctor) {
+  return function() {
+    // Use a `switch` statement to work with class constructors. See
+    // http://ecma-international.org/ecma-262/7.0/#sec-ecmascript-function-objects-call-thisargument-argumentslist
+    // for more details.
+    var args = arguments;
+    switch (args.length) {
+      case 0: return new Ctor;
+      case 1: return new Ctor(args[0]);
+      case 2: return new Ctor(args[0], args[1]);
+      case 3: return new Ctor(args[0], args[1], args[2]);
+      case 4: return new Ctor(args[0], args[1], args[2], args[3]);
+      case 5: return new Ctor(args[0], args[1], args[2], args[3], args[4]);
+      case 6: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5]);
+      case 7: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5], args[6]);
+    }
+    var thisBinding = baseCreate(Ctor.prototype),
+        result = Ctor.apply(thisBinding, args);
+
+    // Mimic the constructor's `return` behavior.
+    // See https://es5.github.io/#x13.2.2 for more details.
+    return isObject(result) ? result : thisBinding;
+  };
+}
+
+module.exports = createCtor;