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/patch-repl.mjs

@@ -0,0 +1 @@
+var i=Object.defineProperty;var a=(t,r)=>i(t,"name",{value:r,configurable:!0});import s from"node:repl";import{transform as f}from"esbuild";const p=a(t=>{const{eval:r}=t,n=a(async function(e,c,o,l){try{e=(await f(e,{sourcefile:o,loader:"ts",tsconfigRaw:{compilerOptions:{preserveValueImports:!0}},define:{require:"global.require"}})).code}catch{}return r.call(this,e,c,o,l)},"preEval");t.eval=n},"patchEval"),{start:u}=s;s.start=function(){const t=Reflect.apply(u,this,arguments);return p(t),t};