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/startsWith.js

@@ -0,0 +1,39 @@
+var baseClamp = require('./_baseClamp'),
+    baseToString = require('./_baseToString'),
+    toInteger = require('./toInteger'),
+    toString = require('./toString');
+
+/**
+ * Checks if `string` starts with the given target string.
+ *
+ * @static
+ * @memberOf _
+ * @since 3.0.0
+ * @category String
+ * @param {string} [string=''] The string to inspect.
+ * @param {string} [target] The string to search for.
+ * @param {number} [position=0] The position to search from.
+ * @returns {boolean} Returns `true` if `string` starts with `target`,
+ *  else `false`.
+ * @example
+ *
+ * _.startsWith('abc', 'a');
+ * // => true
+ *
+ * _.startsWith('abc', 'b');
+ * // => false
+ *
+ * _.startsWith('abc', 'b', 1);
+ * // => true
+ */
+function startsWith(string, target, position) {
+  string = toString(string);
+  position = position == null
+    ? 0
+    : baseClamp(toInteger(position), 0, string.length);
+
+  target = baseToString(target);
+  return string.slice(position, position + target.length) == target;
+}
+
+module.exports = startsWith;