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/regenerate-unicode-properties/Script_Extensions/Oriya.js

@@ -0,0 +1,3 @@
+const set = require('regenerate')(0x1CDA, 0x1CF2);
+set.addRange(0x951, 0x952).addRange(0x964, 0x965).addRange(0xB01, 0xB03).addRange(0xB05, 0xB0C).addRange(0xB0F, 0xB10).addRange(0xB13, 0xB28).addRange(0xB2A, 0xB30).addRange(0xB32, 0xB33).addRange(0xB35, 0xB39).addRange(0xB3C, 0xB44).addRange(0xB47, 0xB48).addRange(0xB4B, 0xB4D).addRange(0xB55, 0xB57).addRange(0xB5C, 0xB5D).addRange(0xB5F, 0xB63).addRange(0xB66, 0xB77);
+exports.characters = set;