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/errors.d.ts

@@ -0,0 +1,9 @@
+import type { TypeError } from "../compile/validate/dataType";
+import type { ApplicatorKeywordError } from "./applicator";
+import type { ValidationKeywordError } from "./validation";
+import type { FormatError } from "./format/format";
+import type { UnevaluatedPropertiesError } from "./unevaluated/unevaluatedProperties";
+import type { UnevaluatedItemsError } from "./unevaluated/unevaluatedItems";
+import type { DependentRequiredError } from "./validation/dependentRequired";
+import type { DiscriminatorError } from "./discriminator";
+export type DefinedError = TypeError | ApplicatorKeywordError | ValidationKeywordError | FormatError | UnevaluatedPropertiesError | UnevaluatedItemsError | DependentRequiredError | DiscriminatorError;