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/shebang-command/readme.md

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+# shebang-command [![Build Status](https://travis-ci.org/kevva/shebang-command.svg?branch=master)](https://travis-ci.org/kevva/shebang-command)
+
+> Get the command from a shebang
+
+
+## Install
+
+```
+$ npm install shebang-command
+```
+
+
+## Usage
+
+```js
+const shebangCommand = require('shebang-command');
+
+shebangCommand('#!/usr/bin/env node');
+//=> 'node'
+
+shebangCommand('#!/bin/bash');
+//=> 'bash'
+```
+
+
+## API
+
+### shebangCommand(string)
+
+#### string
+
+Type: `string`
+
+String containing a shebang.