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/elements.js

@@ -0,0 +1,24 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const util_1 = require("../../compile/util");
+const code_1 = require("../code");
+const codegen_1 = require("../../compile/codegen");
+const metadata_1 = require("./metadata");
+const nullable_1 = require("./nullable");
+const error_1 = require("./error");
+const def = {
+    keyword: "elements",
+    schemaType: "object",
+    error: (0, error_1.typeError)("array"),
+    code(cxt) {
+        (0, metadata_1.checkMetadata)(cxt);
+        const { gen, data, schema, it } = cxt;
+        if ((0, util_1.alwaysValidSchema)(it, schema))
+            return;
+        const [valid] = (0, nullable_1.checkNullable)(cxt);
+        gen.if((0, codegen_1.not)(valid), () => gen.if((0, codegen_1._) `Array.isArray(${data})`, () => gen.assign(valid, (0, code_1.validateArray)(cxt)), () => cxt.error()));
+        cxt.ok(valid);
+    },
+};
+exports.default = def;
+//# sourceMappingURL=elements.js.map