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/validation/index.d.ts

@@ -0,0 +1,16 @@
+import type { ErrorObject, Vocabulary } from "../../types";
+import { LimitNumberError } from "./limitNumber";
+import { MultipleOfError } from "./multipleOf";
+import { PatternError } from "./pattern";
+import { RequiredError } from "./required";
+import { UniqueItemsError } from "./uniqueItems";
+import { ConstError } from "./const";
+import { EnumError } from "./enum";
+declare const validation: Vocabulary;
+export default validation;
+type LimitError = ErrorObject<"maxItems" | "minItems" | "minProperties" | "maxProperties" | "minLength" | "maxLength", {
+    limit: number;
+}, number | {
+    $data: string;
+}>;
+export type ValidationKeywordError = LimitError | LimitNumberError | MultipleOfError | PatternError | RequiredError | UniqueItemsError | ConstError | EnumError;