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/_createRound.js

@@ -0,0 +1,35 @@
+var root = require('./_root'),
+    toInteger = require('./toInteger'),
+    toNumber = require('./toNumber'),
+    toString = require('./toString');
+
+/* Built-in method references for those with the same name as other `lodash` methods. */
+var nativeIsFinite = root.isFinite,
+    nativeMin = Math.min;
+
+/**
+ * Creates a function like `_.round`.
+ *
+ * @private
+ * @param {string} methodName The name of the `Math` method to use when rounding.
+ * @returns {Function} Returns the new round function.
+ */
+function createRound(methodName) {
+  var func = Math[methodName];
+  return function(number, precision) {
+    number = toNumber(number);
+    precision = precision == null ? 0 : nativeMin(toInteger(precision), 292);
+    if (precision && nativeIsFinite(number)) {
+      // Shift with exponential notation to avoid floating-point issues.
+      // See [MDN](https://mdn.io/round#Examples) for more details.
+      var pair = (toString(number) + 'e').split('e'),
+          value = func(pair[0] + 'e' + (+pair[1] + precision));
+
+      pair = (toString(value) + 'e').split('e');
+      return +(pair[0] + 'e' + (+pair[1] - precision));
+    }
+    return func(number);
+  };
+}
+
+module.exports = createRound;