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/toFinite.js

@@ -0,0 +1,42 @@
+var toNumber = require('./toNumber');
+
+/** Used as references for various `Number` constants. */
+var INFINITY = 1 / 0,
+    MAX_INTEGER = 1.7976931348623157e+308;
+
+/**
+ * Converts `value` to a finite number.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.12.0
+ * @category Lang
+ * @param {*} value The value to convert.
+ * @returns {number} Returns the converted number.
+ * @example
+ *
+ * _.toFinite(3.2);
+ * // => 3.2
+ *
+ * _.toFinite(Number.MIN_VALUE);
+ * // => 5e-324
+ *
+ * _.toFinite(Infinity);
+ * // => 1.7976931348623157e+308
+ *
+ * _.toFinite('3.2');
+ * // => 3.2
+ */
+function toFinite(value) {
+  if (!value) {
+    return value === 0 ? value : 0;
+  }
+  value = toNumber(value);
+  if (value === INFINITY || value === -INFINITY) {
+    var sign = (value < 0 ? -1 : 1);
+    return sign * MAX_INTEGER;
+  }
+  return value === value ? value : 0;
+}
+
+module.exports = toFinite;