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/vite/index.cjs

@@ -0,0 +1,60 @@
+warnCjsUsage()
+
+// type utils
+module.exports.defineConfig = (config) => config
+
+// proxy cjs utils (sync functions)
+Object.assign(module.exports, require('./dist/node-cjs/publicUtils.cjs'))
+
+// async functions, can be redirect from ESM build
+const asyncFunctions = [
+  'build',
+  'createServer',
+  'preview',
+  'transformWithEsbuild',
+  'resolveConfig',
+  'optimizeDeps',
+  'formatPostcssSourceMap',
+  'loadConfigFromFile',
+  'preprocessCSS',
+]
+asyncFunctions.forEach((name) => {
+  module.exports[name] = (...args) =>
+    import('./dist/node/index.js').then((i) => i[name](...args))
+})
+
+function warnCjsUsage() {
+  if (process.env.VITE_CJS_IGNORE_WARNING) return
+  const logLevelIndex = process.argv.findIndex((arg) =>
+    /^(?:-l|--logLevel)/.test(arg),
+  )
+  if (logLevelIndex > 0) {
+    const logLevelValue = process.argv[logLevelIndex + 1]
+    if (logLevelValue === 'silent' || logLevelValue === 'error') {
+      return
+    }
+    if (/silent|error/.test(process.argv[logLevelIndex])) {
+      return
+    }
+  }
+  const yellow = (str) => `\u001b[33m${str}\u001b[39m`
+  console.warn(
+    yellow(
+      `The CJS build of Vite's Node API is deprecated. See https://vite.dev/guide/troubleshooting.html#vite-cjs-node-api-deprecated for more details.`,
+    ),
+  )
+  if (process.env.VITE_CJS_TRACE) {
+    const e = {}
+    const stackTraceLimit = Error.stackTraceLimit
+    Error.stackTraceLimit = 100
+    Error.captureStackTrace(e)
+    Error.stackTraceLimit = stackTraceLimit
+    console.log(
+      e.stack
+        .split('\n')
+        .slice(1)
+        .filter((line) => !line.includes('(node:'))
+        .join('\n'),
+    )
+  }
+}