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/tsx/dist/get-pipe-path-BHW2eJdv.mjs

@@ -0,0 +1 @@
+var p=Object.defineProperty;var e=(t,r)=>p(t,"name",{value:r,configurable:!0});import{createRequire as o}from"module";import a from"node:path";import{t as s}from"./temporary-directory-CwHp0_NW.mjs";var m=o(import.meta.url);const i=process.platform==="win32",n=e(t=>{const r=a.join(s,`${t}.pipe`);return i?`\\\\?\\pipe\\${r}`:r},"getPipePath");export{n as g,i,m as r};