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/fast-deep-equal/README.md

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+# fast-deep-equal
+The fastest deep equal with ES6 Map, Set and Typed arrays support.
+
+[![Build Status](https://travis-ci.org/epoberezkin/fast-deep-equal.svg?branch=master)](https://travis-ci.org/epoberezkin/fast-deep-equal)
+[![npm](https://img.shields.io/npm/v/fast-deep-equal.svg)](https://www.npmjs.com/package/fast-deep-equal)
+[![Coverage Status](https://coveralls.io/repos/github/epoberezkin/fast-deep-equal/badge.svg?branch=master)](https://coveralls.io/github/epoberezkin/fast-deep-equal?branch=master)
+
+
+## Install
+
+```bash
+npm install fast-deep-equal
+```
+
+
+## Features
+
+- ES5 compatible
+- works in node.js (8+) and browsers (IE9+)
+- checks equality of Date and RegExp objects by value.
+
+ES6 equal (`require('fast-deep-equal/es6')`) also supports:
+- Maps
+- Sets
+- Typed arrays
+
+
+## Usage
+
+```javascript
+var equal = require('fast-deep-equal');
+console.log(equal({foo: 'bar'}, {foo: 'bar'})); // true
+```
+
+To support ES6 Maps, Sets and Typed arrays equality use:
+
+```javascript
+var equal = require('fast-deep-equal/es6');
+console.log(equal(Int16Array([1, 2]), Int16Array([1, 2]))); // true
+```
+
+To use with React (avoiding the traversal of React elements' _owner
+property that contains circular references and is not needed when
+comparing the elements - borrowed from [react-fast-compare](https://github.com/FormidableLabs/react-fast-compare)):
+
+```javascript
+var equal = require('fast-deep-equal/react');
+var equal = require('fast-deep-equal/es6/react');
+```
+
+
+## Performance benchmark
+
+Node.js v12.6.0:
+
+```
+fast-deep-equal x 261,950 ops/sec ±0.52% (89 runs sampled)
+fast-deep-equal/es6 x 212,991 ops/sec ±0.34% (92 runs sampled)
+fast-equals x 230,957 ops/sec ±0.83% (85 runs sampled)
+nano-equal x 187,995 ops/sec ±0.53% (88 runs sampled)
+shallow-equal-fuzzy x 138,302 ops/sec ±0.49% (90 runs sampled)
+underscore.isEqual x 74,423 ops/sec ±0.38% (89 runs sampled)
+lodash.isEqual x 36,637 ops/sec ±0.72% (90 runs sampled)
+deep-equal x 2,310 ops/sec ±0.37% (90 runs sampled)
+deep-eql x 35,312 ops/sec ±0.67% (91 runs sampled)
+ramda.equals x 12,054 ops/sec ±0.40% (91 runs sampled)
+util.isDeepStrictEqual x 46,440 ops/sec ±0.43% (90 runs sampled)
+assert.deepStrictEqual x 456 ops/sec ±0.71% (88 runs sampled)
+
+The fastest is fast-deep-equal
+```
+
+To run benchmark (requires node.js 6+):
+
+```bash
+npm run benchmark
+```
+
+__Please note__: this benchmark runs against the available test cases. To choose the most performant library for your application, it is recommended to benchmark against your data and to NOT expect this benchmark to reflect the performance difference in your application.
+
+
+## Enterprise support
+
+fast-deep-equal package is a part of [Tidelift enterprise subscription](https://tidelift.com/subscription/pkg/npm-fast-deep-equal?utm_source=npm-fast-deep-equal&utm_medium=referral&utm_campaign=enterprise&utm_term=repo) - it provides a centralised commercial support to open-source software users, in addition to the support provided by software maintainers.
+
+
+## Security contact
+
+To report a security vulnerability, please use the
+[Tidelift security contact](https://tidelift.com/security).
+Tidelift will coordinate the fix and disclosure. Please do NOT report security vulnerability via GitHub issues.
+
+
+## License
+
+[MIT](https://github.com/epoberezkin/fast-deep-equal/blob/master/LICENSE)