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/@babel/plugin-proposal-private-property-in-object/README.md

@@ -0,0 +1,23 @@
+# @babel/plugin-proposal-private-property-in-object
+
+> ⚠️ This version of the package (`v7.21.0-placeholder-for-preset-env.1`) is not meant to
+> be imported. Use any other version of this plugin or, even better, the
+> [@babel/plugin-transform-private-property-in-object](https://babeljs.io/docs/en/babel-plugin-transform-private-property-in-object) package.
+
+> This plugin transforms checks for a private property in an object
+
+See our website [@babel/plugin-proposal-private-property-in-object](https://babeljs.io/docs/en/babel-plugin-proposal-private-property-in-object) for more information.
+
+## Install
+
+Using npm:
+
+```sh
+npm install --save-dev @babel/plugin-proposal-private-property-in-object
+```
+
+or using yarn:
+
+```sh
+yarn add @babel/plugin-proposal-private-property-in-object --dev
+```