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/chai/lib/chai.js

@@ -0,0 +1,66 @@
+/*!
+ * chai
+ * Copyright(c) 2011-2014 Jake Luer <jake@alogicalparadox.com>
+ * MIT Licensed
+ */
+
+import * as util from './chai/utils/index.js';
+import {AssertionError} from 'assertion-error';
+import {config} from './chai/config.js';
+import './chai/core/assertions.js';
+import {expect} from './chai/interface/expect.js';
+import {Assertion} from './chai/assertion.js';
+import * as should from './chai/interface/should.js';
+import {assert} from './chai/interface/assert.js';
+
+const used = [];
+
+// Assertion Error
+export {AssertionError};
+
+/**
+ * # .use(function)
+ *
+ * Provides a way to extend the internals of Chai.
+ *
+ * @param {Function} fn
+ * @returns {this} for chaining
+ * @public
+ */
+export function use(fn) {
+  const exports = {
+    use,
+    AssertionError,
+    util,
+    config,
+    expect,
+    assert,
+    Assertion,
+    ...should
+  };
+
+  if (!~used.indexOf(fn)) {
+    fn(exports, util);
+    used.push(fn);
+  }
+
+  return exports;
+}
+
+// Utility Functions
+export {util};
+
+// Configuration
+export {config};
+
+// Primary `Assertion` prototype
+export * from './chai/assertion.js';
+
+// Expect interface
+export * from './chai/interface/expect.js';
+
+// Should interface
+export * from './chai/interface/should.js';
+
+// Assert interface
+export * from './chai/interface/assert.js';