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/lib/vocabularies/draft7.ts

@@ -0,0 +1,17 @@
+import type {Vocabulary} from "../types"
+import coreVocabulary from "./core"
+import validationVocabulary from "./validation"
+import getApplicatorVocabulary from "./applicator"
+import formatVocabulary from "./format"
+import {metadataVocabulary, contentVocabulary} from "./metadata"
+
+const draft7Vocabularies: Vocabulary[] = [
+  coreVocabulary,
+  validationVocabulary,
+  getApplicatorVocabulary(),
+  formatVocabulary,
+  metadataVocabulary,
+  contentVocabulary,
+]
+
+export default draft7Vocabularies