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/fs-extra/lib/move/index.js

@@ -0,0 +1,6 @@
+'use strict'
+
+const u = require('universalify').fromCallback
+module.exports = {
+  move: u(require('./move'))
+}

pwa/node_modules/fs-extra/lib/move/move.js

@@ -0,0 +1,65 @@
+'use strict'
+
+const fs = require('graceful-fs')
+const path = require('path')
+const copy = require('../copy').copy
+const remove = require('../remove').remove
+const mkdirp = require('../mkdirs').mkdirp
+const pathExists = require('../path-exists').pathExists
+const stat = require('../util/stat')
+
+function move (src, dest, opts, cb) {
+  if (typeof opts === 'function') {
+    cb = opts
+    opts = {}
+  }
+
+  const overwrite = opts.overwrite || opts.clobber || false
+
+  stat.checkPaths(src, dest, 'move', (err, stats) => {
+    if (err) return cb(err)
+    const { srcStat } = stats
+    stat.checkParentPaths(src, srcStat, dest, 'move', err => {
+      if (err) return cb(err)
+      mkdirp(path.dirname(dest), err => {
+        if (err) return cb(err)
+        return doRename(src, dest, overwrite, cb)
+      })
+    })
+  })
+}
+
+function doRename (src, dest, overwrite, cb) {
+  if (overwrite) {
+    return remove(dest, err => {
+      if (err) return cb(err)
+      return rename(src, dest, overwrite, cb)
+    })
+  }
+  pathExists(dest, (err, destExists) => {
+    if (err) return cb(err)
+    if (destExists) return cb(new Error('dest already exists.'))
+    return rename(src, dest, overwrite, cb)
+  })
+}
+
+function rename (src, dest, overwrite, cb) {
+  fs.rename(src, dest, err => {
+    if (!err) return cb()
+    if (err.code !== 'EXDEV') return cb(err)
+    return moveAcrossDevice(src, dest, overwrite, cb)
+  })
+}
+
+function moveAcrossDevice (src, dest, overwrite, cb) {
+  const opts = {
+    overwrite,
+    errorOnExist: true
+  }
+  copy(src, dest, opts, err => {
+    if (err) return cb(err)
+    return remove(src, cb)
+  })
+}
+
+module.exports = move