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/has-proto/test/mutator.js

@@ -0,0 +1,34 @@
+'use strict';
+
+var test = require('tape');
+var gPO = require('reflect.getprototypeof/polyfill')();
+var gOPD = require('gopd');
+
+var hasProto = require('../');
+var hasProtoMutator = require('../mutator');
+
+var getter = require('dunder-proto/get');
+
+test('hasProtoMutator', function (t) {
+	var result = hasProtoMutator();
+	t.equal(typeof result, 'boolean', 'returns a boolean (' + result + ')');
+
+	var obj = { __proto__: null };
+	if (result) {
+		t.notOk('toString' in obj, 'null object lacks toString');
+		t.equal(gPO(obj), null);
+		if (gOPD && getter) {
+			t.equal(getter(obj), null);
+		}
+	} else if (hasProto()) {
+		t.notOk('toString' in obj, 'null object lacks toString');
+		if (gOPD && getter) {
+			t.equal(getter(obj), null);
+		}
+	} else {
+		t.ok('toString' in obj, 'without proto, null object has toString');
+		t.equal(gPO(obj), Object.prototype);
+	}
+
+	t.end();
+});