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/preset-env/lib/polyfills/babel-polyfill.cjs

@@ -0,0 +1,68 @@
+const {
+  getImportSource,
+  getRequireSource,
+  isPolyfillSource
+} = require("./utils.cjs");
+const BABEL_POLYFILL_DEPRECATION = `
+  \`@babel/polyfill\` is deprecated. Please, use required parts of \`core-js\`
+  and \`regenerator-runtime/runtime\` separately`;
+const NO_DIRECT_POLYFILL_IMPORT = `
+  When setting \`useBuiltIns: 'usage'\`, polyfills are automatically imported when needed.
+  Please remove the direct import of \`SPECIFIER\` or use \`useBuiltIns: 'entry'\` instead.`;
+module.exports = function ({
+  template
+}, {
+  regenerator,
+  deprecated,
+  usage
+}) {
+  return {
+    name: "preset-env/replace-babel-polyfill",
+    visitor: {
+      ImportDeclaration(path) {
+        const src = getImportSource(path);
+        if (usage && isPolyfillSource(src)) {
+          console.warn(NO_DIRECT_POLYFILL_IMPORT.replace("SPECIFIER", src));
+          if (!deprecated) path.remove();
+        } else if (src === "@babel/polyfill") {
+          if (deprecated) {
+            console.warn(BABEL_POLYFILL_DEPRECATION);
+          } else if (regenerator) {
+            path.replaceWithMultiple(template.ast`
+              import "core-js";
+              import "regenerator-runtime/runtime.js";
+            `);
+          } else {
+            path.replaceWith(template.ast`
+              import "core-js";
+            `);
+          }
+        }
+      },
+      Program(path) {
+        path.get("body").forEach(bodyPath => {
+          const src = getRequireSource(bodyPath);
+          if (usage && isPolyfillSource(src)) {
+            console.warn(NO_DIRECT_POLYFILL_IMPORT.replace("SPECIFIER", src));
+            if (!deprecated) bodyPath.remove();
+          } else if (src === "@babel/polyfill") {
+            if (deprecated) {
+              console.warn(BABEL_POLYFILL_DEPRECATION);
+            } else if (regenerator) {
+              bodyPath.replaceWithMultiple(template.ast`
+                require("core-js");
+                require("regenerator-runtime/runtime.js");
+              `);
+            } else {
+              bodyPath.replaceWith(template.ast`
+                require("core-js");
+              `);
+            }
+          }
+        });
+      }
+    }
+  };
+};
+
+//# sourceMappingURL=babel-polyfill.cjs.map