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/jsonpointer/README.md

@@ -0,0 +1,45 @@
+# JSON Pointer for Node.js
+
+This is an implementation of [JSON Pointer](https://tools.ietf.org/html/rfc6901).
+
+## CLI
+
+Looking to filter JSON from the command line? Check out [jsonpointer-cli](https://github.com/joeyespo/jsonpointer-cli).
+
+## Usage
+```javascript
+var jsonpointer = require('jsonpointer');
+var obj = { foo: 1, bar: { baz: 2}, qux: [3, 4, 5]};
+
+jsonpointer.get(obj, '/foo');     // returns 1
+jsonpointer.get(obj, '/bar/baz'); // returns 2
+jsonpointer.get(obj, '/qux/0');   // returns 3
+jsonpointer.get(obj, '/qux/1');   // returns 4
+jsonpointer.get(obj, '/qux/2');   // returns 5
+jsonpointer.get(obj, '/quo');     // returns undefined
+
+jsonpointer.set(obj, '/foo', 6);  // sets obj.foo = 6;
+jsonpointer.set(obj, '/qux/-', 6) // sets obj.qux = [3, 4, 5, 6]
+
+var pointer = jsonpointer.compile('/foo')
+pointer.get(obj)    // returns 1
+pointer.set(obj, 1) // sets obj.foo = 1
+```
+
+## Testing
+
+    $ npm test
+    All tests pass.
+    $
+
+[![Node.js CI](https://github.com/janl/node-jsonpointer/actions/workflows/node.js.yml/badge.svg)](https://github.com/janl/node-jsonpointer/actions/workflows/node.js.yml)
+
+## Author
+
+(c) 2011-2021 Jan Lehnardt <jan@apache.org> & Marc Bachmann <https://github.com/marcbachmann>
+
+Thanks to all contributors.
+
+## License
+
+MIT License.