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/error.js

@@ -0,0 +1,35 @@
+import { inspectList, inspectProperty, truncate } from './helpers.js';
+const errorKeys = [
+    'stack',
+    'line',
+    'column',
+    'name',
+    'message',
+    'fileName',
+    'lineNumber',
+    'columnNumber',
+    'number',
+    'description',
+    'cause',
+];
+export default function inspectObject(error, options) {
+    const properties = Object.getOwnPropertyNames(error).filter(key => errorKeys.indexOf(key) === -1);
+    const name = error.name;
+    options.truncate -= name.length;
+    let message = '';
+    if (typeof error.message === 'string') {
+        message = truncate(error.message, options.truncate);
+    }
+    else {
+        properties.unshift('message');
+    }
+    message = message ? `: ${message}` : '';
+    options.truncate -= message.length + 5;
+    options.seen = options.seen || [];
+    if (options.seen.includes(error)) {
+        return '[Circular]';
+    }
+    options.seen.push(error);
+    const propertyContents = inspectList(properties.map(key => [key, error[key]]), options, inspectProperty);
+    return `${name}${message}${propertyContents ? ` { ${propertyContents} }` : ''}`;
+}