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/require-from-string/readme.md

@@ -0,0 +1,56 @@
+# require-from-string [![Build Status](https://travis-ci.org/floatdrop/require-from-string.svg?branch=master)](https://travis-ci.org/floatdrop/require-from-string)
+
+Load module from string in Node.
+
+## Install
+
+```
+$ npm install --save require-from-string
+```
+
+
+## Usage
+
+```js
+var requireFromString = require('require-from-string');
+
+requireFromString('module.exports = 1');
+//=> 1
+```
+
+
+## API
+
+### requireFromString(code, [filename], [options])
+
+#### code
+
+*Required*  
+Type: `string`
+
+Module code.
+
+#### filename
+Type: `string`  
+Default: `''`
+
+Optional filename.
+
+
+#### options
+Type: `object`
+
+##### appendPaths
+Type: `Array`
+
+List of `paths`, that will be appended to module `paths`. Useful, when you want
+to be able require modules from these paths.
+
+##### prependPaths
+Type: `Array`
+
+Same as `appendPaths`, but paths will be prepended.
+
+## License
+
+MIT © [Vsevolod Strukchinsky](http://github.com/floatdrop)