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/object-inspect/test/holes.js

@@ -0,0 +1,15 @@
+var test = require('tape');
+var inspect = require('../');
+
+var xs = ['a', 'b'];
+xs[5] = 'f';
+xs[7] = 'j';
+xs[8] = 'k';
+
+test('holes', function (t) {
+    t.plan(1);
+    t.equal(
+        inspect(xs),
+        "[ 'a', 'b', , , , 'f', , 'j', 'k' ]"
+    );
+});