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/cli.js

@@ -0,0 +1,42 @@
+#!/usr/bin/env node
+
+let { readFileSync } = require('fs')
+let { join } = require('path')
+
+require('./check-npm-version')
+let updateDb = require('./')
+
+const ROOT = __dirname
+
+function getPackage() {
+  return JSON.parse(readFileSync(join(ROOT, 'package.json')))
+}
+
+let args = process.argv.slice(2)
+
+let USAGE = 'Usage:\n  npx update-browserslist-db\n'
+
+function isArg(arg) {
+  return args.some(i => i === arg)
+}
+
+function error(msg) {
+  process.stderr.write('update-browserslist-db: ' + msg + '\n')
+  process.exit(1)
+}
+
+if (isArg('--help') || isArg('-h')) {
+  process.stdout.write(getPackage().description + '.\n\n' + USAGE + '\n')
+} else if (isArg('--version') || isArg('-v')) {
+  process.stdout.write('browserslist-lint ' + getPackage().version + '\n')
+} else {
+  try {
+    updateDb()
+  } catch (e) {
+    if (e.name === 'BrowserslistUpdateError') {
+      error(e.message)
+    } else {
+      throw e
+    }
+  }
+}