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/isarray/README.md

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+
+# isarray
+
+`Array#isArray` for older browsers and deprecated Node.js versions.
+
+[![build status](https://secure.travis-ci.org/juliangruber/isarray.svg)](http://travis-ci.org/juliangruber/isarray)
+[![downloads](https://img.shields.io/npm/dm/isarray.svg)](https://www.npmjs.org/package/isarray)
+
+[![browser support](https://ci.testling.com/juliangruber/isarray.png)
+](https://ci.testling.com/juliangruber/isarray)
+
+__Just use Array.isArray directly__, unless you need to support those older versions.
+
+## Usage
+
+```js
+var isArray = require('isarray');
+
+console.log(isArray([])); // => true
+console.log(isArray({})); // => false
+```
+
+## Installation
+
+With [npm](https://npmjs.org) do
+
+```bash
+$ npm install isarray
+```
+
+Then bundle for the browser with
+[browserify](https://github.com/substack/node-browserify).
+
+## Sponsors
+
+This module is proudly supported by my [Sponsors](https://github.com/juliangruber/sponsors)!
+
+Do you want to support modules like this to improve their quality, stability and weigh in on new features? Then please consider donating to my [Patreon](https://www.patreon.com/juliangruber). Not sure how much of my modules you're using? Try [feross/thanks](https://github.com/feross/thanks)!