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/supports-preserve-symlinks-flag/test/index.js

@@ -0,0 +1,29 @@
+'use strict';
+
+var test = require('tape');
+var semver = require('semver');
+
+var supportsPreserveSymlinks = require('../');
+var browser = require('../browser');
+
+test('supportsPreserveSymlinks', function (t) {
+	t.equal(typeof supportsPreserveSymlinks, 'boolean', 'is a boolean');
+
+	t.equal(browser, null, 'browser file is `null`');
+	t.equal(
+		supportsPreserveSymlinks,
+		null,
+		'in a browser, is null',
+		{ skip: typeof window === 'undefined' }
+	);
+
+	var expected = semver.satisfies(process.version, '>= 6.2');
+	t.equal(
+		supportsPreserveSymlinks,
+		expected,
+		'is true in node v6.2+, false otherwise (actual: ' + supportsPreserveSymlinks + ', expected ' + expected + ')',
+		{ skip: typeof window !== 'undefined' }
+	);
+
+	t.end();
+});