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/leaflet.offline/test/TileLayerTest.ts

@@ -0,0 +1,136 @@
+import { Bounds, Point } from 'leaflet';
+import { assert } from 'chai';
+import { TileLayerOffline } from '../src/TileLayerOffline';
+
+describe('TileLayer.Offline', () => {
+  it('createTile', () => {
+    const url = 'http://a.tile.openstreetmap.org/{z}/{x}/{y}.png';
+    const layer = new TileLayerOffline(url);
+    // @ts-ignore
+    const tile = layer.createTile({ x: 123456, y: 456789, z: 16 }, () => {});
+    assert.instanceOf(tile, HTMLElement);
+  });
+  it('get storagekey openstreetmap', () => {
+    const layer = new TileLayerOffline(
+      'http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',
+    );
+    const key = layer._getStorageKey({ z: 16, x: 123456, y: 456789 });
+    assert.equal(key, 'http://a.tile.openstreetmap.org/16/123456/456789.png');
+  });
+  it('get storagekey cartodb', () => {
+    const layer = new TileLayerOffline(
+      'https://cartodb-basemaps-{s}.global.ssl.fastly.net/light_all/{z}/{x}/{y}.png',
+    );
+    const key = layer._getStorageKey({ z: 16, x: 123456, y: 456789 });
+    assert.equal(
+      key,
+      'https://cartodb-basemaps-a.global.ssl.fastly.net/light_all/16/123456/456789.png',
+    );
+  });
+  it('get storagekey mapbox with accessToken', () => {
+    const layer = new TileLayerOffline(
+      'https://api.tiles.mapbox.com/v4/{id}/{z}/{x}/{y}.png?access_token={accessToken}',
+      {
+        id: 'mapbox.streets',
+        accessToken: 'xyz',
+      },
+    );
+    const key = layer._getStorageKey({ z: 16, x: 123456, y: 456789 });
+    assert.equal(
+      key,
+      'https://api.tiles.mapbox.com/v4/mapbox.streets/16/123456/456789.png?access_token=xyz',
+    );
+  });
+  it('calculates tiles at level 16', () => {
+    const layer = new TileLayerOffline(
+      'http://a.tile.openstreetmap.org/{z}/{x}/{y}.png',
+    );
+    const bounds = new Bounds(
+      new Point(8621975, 5543267.999999999),
+      new Point(8621275, 5542538),
+    );
+    const tiles = layer.getTileUrls(bounds, 16);
+    assert.lengthOf(tiles, 16);
+    const urls = tiles.map((t) => t.url);
+    assert.include(urls, 'http://a.tile.openstreetmap.org/16/33677/21651.png');
+    const keys = tiles.map((t) => t.key);
+    assert.include(keys, 'http://a.tile.openstreetmap.org/16/33677/21651.png');
+  });
+
+  it('calculates tile urls,keys at level 16 with subdomains', () => {
+    const layer = new TileLayerOffline(
+      'http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',
+    );
+    const bounds = new Bounds(
+      new Point(8621975, 5543267.999999999),
+      new Point(8621275, 5542538),
+    );
+    const tiles = layer.getTileUrls(bounds, 16);
+    assert.lengthOf(tiles, 16);
+    const urls = tiles.map((t) => t.url.replace(/[abc]\./, ''));
+    assert.include(urls, 'http://tile.openstreetmap.org/16/33677/21651.png');
+    const keys = tiles.map((t) => t.key);
+    assert.include(keys, 'http://a.tile.openstreetmap.org/16/33677/21651.png');
+  });
+
+  it('uses subdomains for url and not for key', () => {
+    const layer = new TileLayerOffline(
+      'http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',
+    );
+    const bounds = new Bounds(
+      new Point(8621975, 5543267.999999999),
+      new Point(8621275, 5542538),
+    );
+    const tiles = layer.getTileUrls(bounds, 16);
+    const subs = tiles.map((t) => t.url.match(/([abc])\./)?.[1]);
+    assert.include(subs, 'a');
+    assert.include(subs, 'b');
+    assert.include(subs, 'c');
+    const subskeys = tiles.map((t) => t.key.match(/([abc])\./)?.[1]);
+    assert.include(subskeys, 'a');
+    assert.notInclude(subskeys, 'b');
+    assert.notInclude(subskeys, 'c');
+  });
+
+  it('calculates openstreetmap tiles at level 16', () => {
+    const layer = new TileLayerOffline(
+      'http://a.tile.openstreetmap.org/{z}/{x}/{y}.png',
+    );
+    const bounds = new Bounds(
+      new Point(8621975, 5543267.999999999),
+      new Point(8621275, 5542538),
+    );
+    const tiles = layer.getTileUrls(bounds, 16);
+    assert.lengthOf(tiles, 16);
+    const urls = tiles.map((t) => t.url);
+    assert.include(urls, 'http://a.tile.openstreetmap.org/16/33677/21651.png');
+    const keys = tiles.map((t) => t.key);
+    assert.include(keys, 'http://a.tile.openstreetmap.org/16/33677/21651.png');
+  });
+
+  it('calculates mobox tiles at level 16', () => {
+    const layer = new TileLayerOffline(
+      'https://api.tiles.mapbox.com/v4/{id}/{z}/{x}/{y}.png?access_token={accessToken}',
+      {
+        id: 'mapbox.streets',
+        accessToken: 'xyz',
+      },
+    );
+    const bounds = new Bounds(
+      new Point(8621975, 5543267.999999999),
+      new Point(8621275, 5542538),
+    );
+    const tiles = layer.getTileUrls(bounds, 16);
+    assert.lengthOf(tiles, 16);
+    const urls = tiles.map((t) => t.url);
+    assert.include(
+      urls,
+      'https://api.tiles.mapbox.com/v4/mapbox.streets/16/33677/21651.png?access_token=xyz',
+    );
+    const keys = tiles.map((t) => t.key);
+    assert.include(
+      keys,
+      'https://api.tiles.mapbox.com/v4/mapbox.streets/16/33677/21651.png?access_token=xyz',
+    );
+  });
+});