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/jake/usage.txt

@@ -0,0 +1,17 @@
+Jake JavaScript build tool
+********************************************************************************
+If no flags are given, Jake looks for a Jakefile or Jakefile.js in the current directory.
+********************************************************************************
+{Usage}: jake [options ...] [env variables ...] target
+
+{Options}:
+  -f,      --jakefile FILE          Use FILE as the Jakefile.
+  -C,      --directory DIRECTORY    Change to DIRECTORY before running tasks.
+  -q,      --quiet                  Do not log messages to standard output.
+  -B,      --always-make            Unconditionally make all targets.
+  -T/-ls,  --tasks                  Display the tasks (matching optional PATTERN) with descriptions, then exit.
+  -J,      --jakelibdir JAKELIBDIR  Auto-import any .jake files in JAKELIBDIR. (default is \'jakelib\')
+  -h,      --help                   Display this help message.
+  -V/-v,   --version                Display the Jake version.
+  -ar,     --allow-rejection        Keep running even after unhandled promise rejection.
+