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/postcss/lib/result.js

@@ -0,0 +1,42 @@
+'use strict'
+
+let Warning = require('./warning')
+
+class Result {
+  get content() {
+    return this.css
+  }
+
+  constructor(processor, root, opts) {
+    this.processor = processor
+    this.messages = []
+    this.root = root
+    this.opts = opts
+    this.css = ''
+    this.map = undefined
+  }
+
+  toString() {
+    return this.css
+  }
+
+  warn(text, opts = {}) {
+    if (!opts.plugin) {
+      if (this.lastPlugin && this.lastPlugin.postcssPlugin) {
+        opts.plugin = this.lastPlugin.postcssPlugin
+      }
+    }
+
+    let warning = new Warning(text, opts)
+    this.messages.push(warning)
+
+    return warning
+  }
+
+  warnings() {
+    return this.messages.filter(i => i.type === 'warning')
+  }
+}
+
+module.exports = Result
+Result.default = Result