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-polyfill-regenerator/lib/index.js

@@ -0,0 +1,47 @@
+"use strict";
+
+exports.__esModule = true;
+exports.default = void 0;
+var _helperDefinePolyfillProvider = _interopRequireDefault(require("@babel/helper-define-polyfill-provider"));
+function _interopRequireDefault(e) { return e && e.__esModule ? e : { default: e }; }
+const runtimeCompat = "#__secret_key__@babel/runtime__compatibility";
+var _default = exports.default = (0, _helperDefinePolyfillProvider.default)(({
+  debug,
+  targets,
+  babel
+}, options) => {
+  if (!shallowEqual(targets, babel.targets())) {
+    throw new Error("This plugin does not use the targets option. Only preset-env's targets" + " or top-level targets need to be configured for this plugin to work." + " See https://github.com/babel/babel-polyfills/issues/36 for more" + " details.");
+  }
+  const {
+    [runtimeCompat]: {
+      moduleName = null,
+      useBabelRuntime = false
+    } = {}
+  } = options;
+  return {
+    name: "regenerator",
+    polyfills: ["regenerator-runtime"],
+    usageGlobal(meta, utils) {
+      if (isRegenerator(meta)) {
+        debug("regenerator-runtime");
+        utils.injectGlobalImport("regenerator-runtime/runtime.js");
+      }
+    },
+    usagePure(meta, utils, path) {
+      if (isRegenerator(meta)) {
+        let pureName = "regenerator-runtime";
+        if (useBabelRuntime) {
+          var _ref;
+          const runtimeName = (_ref = moduleName != null ? moduleName : path.hub.file.get("runtimeHelpersModuleName")) != null ? _ref : "@babel/runtime";
+          pureName = `${runtimeName}/regenerator`;
+        }
+        path.replaceWith(utils.injectDefaultImport(pureName, "regenerator-runtime"));
+      }
+    }
+  };
+});
+const isRegenerator = meta => meta.kind === "global" && meta.name === "regeneratorRuntime";
+function shallowEqual(obj1, obj2) {
+  return JSON.stringify(obj1) === JSON.stringify(obj2);
+}