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/update-browserslist-db/utils.js

@@ -0,0 +1,25 @@
+const { EOL } = require('os')
+
+const getFirstRegexpMatchOrDefault = (text, regexp, defaultValue) => {
+  regexp.lastIndex = 0 // https://stackoverflow.com/a/11477448/4536543
+  let match = regexp.exec(text)
+  if (match !== null) {
+    return match[1]
+  } else {
+    return defaultValue
+  }
+}
+
+const DEFAULT_INDENT = '  '
+const INDENT_REGEXP = /^([ \t]+)[^\s]/m
+
+module.exports.detectIndent = text =>
+  getFirstRegexpMatchOrDefault(text, INDENT_REGEXP, DEFAULT_INDENT)
+module.exports.DEFAULT_INDENT = DEFAULT_INDENT
+
+const DEFAULT_EOL = EOL
+const EOL_REGEXP = /(\r\n|\n|\r)/g
+
+module.exports.detectEOL = text =>
+  getFirstRegexpMatchOrDefault(text, EOL_REGEXP, DEFAULT_EOL)
+module.exports.DEFAULT_EOL = DEFAULT_EOL