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/ajv/dist/vocabularies/jtd/metadata.js

@@ -0,0 +1,25 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.checkMetadata = void 0;
+const util_1 = require("../../compile/util");
+const def = {
+    keyword: "metadata",
+    schemaType: "object",
+    code(cxt) {
+        checkMetadata(cxt);
+        const { gen, schema, it } = cxt;
+        if ((0, util_1.alwaysValidSchema)(it, schema))
+            return;
+        const valid = gen.name("valid");
+        cxt.subschema({ keyword: "metadata", jtdMetadata: true }, valid);
+        cxt.ok(valid);
+    },
+};
+function checkMetadata({ it, keyword }, metadata) {
+    if (it.jtdMetadata !== metadata) {
+        throw new Error(`JTD: "${keyword}" cannot be used in this schema location`);
+    }
+}
+exports.checkMetadata = checkMetadata;
+exports.default = def;
+//# sourceMappingURL=metadata.js.map