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/@babel/plugin-transform-modules-commonjs/lib/dynamic-import.js

@@ -0,0 +1,16 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.transformDynamicImport = transformDynamicImport;
+var _core = require("@babel/core");
+var _helperModuleTransforms = require("@babel/helper-module-transforms");
+const requireNoInterop = source => _core.template.expression.ast`require(${source})`;
+const requireInterop = (source, file) => _core.types.callExpression(file.addHelper("interopRequireWildcard"), [requireNoInterop(source)]);
+function transformDynamicImport(path, noInterop, file) {
+  const buildRequire = noInterop ? requireNoInterop : requireInterop;
+  path.replaceWith((0, _helperModuleTransforms.buildDynamicImport)(path.node, true, false, specifier => buildRequire(specifier, file)));
+}
+
+//# sourceMappingURL=dynamic-import.js.map