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/workbox-navigation-preload/build/workbox-navigation-preload.dev.js

@@ -0,0 +1,99 @@
+this.workbox = this.workbox || {};
+this.workbox.navigationPreload = (function (exports, logger_js) {
+    'use strict';
+
+    // @ts-ignore
+    try {
+      self['workbox:navigation-preload:7.3.0'] && _();
+    } catch (e) {}
+
+    /*
+      Copyright 2018 Google LLC
+
+      Use of this source code is governed by an MIT-style
+      license that can be found in the LICENSE file or at
+      https://opensource.org/licenses/MIT.
+    */
+    /**
+     * @return {boolean} Whether or not the current browser supports enabling
+     * navigation preload.
+     *
+     * @memberof workbox-navigation-preload
+     */
+    function isSupported() {
+      return Boolean(self.registration && self.registration.navigationPreload);
+    }
+
+    /*
+      Copyright 2018 Google LLC
+
+      Use of this source code is governed by an MIT-style
+      license that can be found in the LICENSE file or at
+      https://opensource.org/licenses/MIT.
+    */
+    /**
+     * If the browser supports Navigation Preload, then this will disable it.
+     *
+     * @memberof workbox-navigation-preload
+     */
+    function disable() {
+      if (isSupported()) {
+        self.addEventListener('activate', event => {
+          event.waitUntil(self.registration.navigationPreload.disable().then(() => {
+            {
+              logger_js.logger.log(`Navigation preload is disabled.`);
+            }
+          }));
+        });
+      } else {
+        {
+          logger_js.logger.log(`Navigation preload is not supported in this browser.`);
+        }
+      }
+    }
+
+    /*
+      Copyright 2018 Google LLC
+
+      Use of this source code is governed by an MIT-style
+      license that can be found in the LICENSE file or at
+      https://opensource.org/licenses/MIT.
+    */
+    /**
+     * If the browser supports Navigation Preload, then this will enable it.
+     *
+     * @param {string} [headerValue] Optionally, allows developers to
+     * [override](https://developers.google.com/web/updates/2017/02/navigation-preload#changing_the_header)
+     * the value of the `Service-Worker-Navigation-Preload` header which will be
+     * sent to the server when making the navigation request.
+     *
+     * @memberof workbox-navigation-preload
+     */
+    function enable(headerValue) {
+      if (isSupported()) {
+        self.addEventListener('activate', event => {
+          event.waitUntil(self.registration.navigationPreload.enable().then(() => {
+            // Defaults to Service-Worker-Navigation-Preload: true if not set.
+            if (headerValue) {
+              void self.registration.navigationPreload.setHeaderValue(headerValue);
+            }
+            {
+              logger_js.logger.log(`Navigation preload is enabled.`);
+            }
+          }));
+        });
+      } else {
+        {
+          logger_js.logger.log(`Navigation preload is not supported in this browser.`);
+        }
+      }
+    }
+
+    exports.disable = disable;
+    exports.enable = enable;
+    exports.isSupported = isSupported;
+
+    return exports;
+
+})({}, workbox.core._private);
+//# sourceMappingURL=workbox-navigation-preload.dev.js.map