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/loupe/lib/regexp.js

@@ -0,0 +1,7 @@
+import { truncate } from './helpers.js';
+export default function inspectRegExp(value, options) {
+    const flags = value.toString().split('/')[2];
+    const sourceLength = options.truncate - (2 + flags.length);
+    const source = value.source;
+    return options.stylize(`/${truncate(source, sourceLength)}/${flags}`, 'regexp');
+}