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-routing/Route.js

@@ -0,0 +1,60 @@
+/*
+  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.
+*/
+import { assert } from 'workbox-core/_private/assert.js';
+import { defaultMethod, validMethods } from './utils/constants.js';
+import { normalizeHandler } from './utils/normalizeHandler.js';
+import './_version.js';
+/**
+ * A `Route` consists of a pair of callback functions, "match" and "handler".
+ * The "match" callback determine if a route should be used to "handle" a
+ * request by returning a non-falsy value if it can. The "handler" callback
+ * is called when there is a match and should return a Promise that resolves
+ * to a `Response`.
+ *
+ * @memberof workbox-routing
+ */
+class Route {
+    /**
+     * Constructor for Route class.
+     *
+     * @param {workbox-routing~matchCallback} match
+     * A callback function that determines whether the route matches a given
+     * `fetch` event by returning a non-falsy value.
+     * @param {workbox-routing~handlerCallback} handler A callback
+     * function that returns a Promise resolving to a Response.
+     * @param {string} [method='GET'] The HTTP method to match the Route
+     * against.
+     */
+    constructor(match, handler, method = defaultMethod) {
+        if (process.env.NODE_ENV !== 'production') {
+            assert.isType(match, 'function', {
+                moduleName: 'workbox-routing',
+                className: 'Route',
+                funcName: 'constructor',
+                paramName: 'match',
+            });
+            if (method) {
+                assert.isOneOf(method, validMethods, { paramName: 'method' });
+            }
+        }
+        // These values are referenced directly by Router so cannot be
+        // altered by minificaton.
+        this.handler = normalizeHandler(handler);
+        this.match = match;
+        this.method = method;
+    }
+    /**
+     *
+     * @param {workbox-routing-handlerCallback} handler A callback
+     * function that returns a Promise resolving to a Response
+     */
+    setCatchHandler(handler) {
+        this.catchHandler = normalizeHandler(handler);
+    }
+}
+export { Route };