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/path-parse/index.js

@@ -0,0 +1,75 @@
+'use strict';
+
+var isWindows = process.platform === 'win32';
+
+// Regex to split a windows path into into [dir, root, basename, name, ext]
+var splitWindowsRe =
+    /^(((?:[a-zA-Z]:|[\\\/]{2}[^\\\/]+[\\\/]+[^\\\/]+)?[\\\/]?)(?:[^\\\/]*[\\\/])*)((\.{1,2}|[^\\\/]+?|)(\.[^.\/\\]*|))[\\\/]*$/;
+
+var win32 = {};
+
+function win32SplitPath(filename) {
+  return splitWindowsRe.exec(filename).slice(1);
+}
+
+win32.parse = function(pathString) {
+  if (typeof pathString !== 'string') {
+    throw new TypeError(
+        "Parameter 'pathString' must be a string, not " + typeof pathString
+    );
+  }
+  var allParts = win32SplitPath(pathString);
+  if (!allParts || allParts.length !== 5) {
+    throw new TypeError("Invalid path '" + pathString + "'");
+  }
+  return {
+    root: allParts[1],
+    dir: allParts[0] === allParts[1] ? allParts[0] : allParts[0].slice(0, -1),
+    base: allParts[2],
+    ext: allParts[4],
+    name: allParts[3]
+  };
+};
+
+
+
+// Split a filename into [dir, root, basename, name, ext], unix version
+// 'root' is just a slash, or nothing.
+var splitPathRe =
+    /^((\/?)(?:[^\/]*\/)*)((\.{1,2}|[^\/]+?|)(\.[^.\/]*|))[\/]*$/;
+var posix = {};
+
+
+function posixSplitPath(filename) {
+  return splitPathRe.exec(filename).slice(1);
+}
+
+
+posix.parse = function(pathString) {
+  if (typeof pathString !== 'string') {
+    throw new TypeError(
+        "Parameter 'pathString' must be a string, not " + typeof pathString
+    );
+  }
+  var allParts = posixSplitPath(pathString);
+  if (!allParts || allParts.length !== 5) {
+    throw new TypeError("Invalid path '" + pathString + "'");
+  }
+  
+  return {
+    root: allParts[1],
+    dir: allParts[0].slice(0, -1),
+    base: allParts[2],
+    ext: allParts[4],
+    name: allParts[3],
+  };
+};
+
+
+if (isWindows)
+  module.exports = win32.parse;
+else /* posix */
+  module.exports = posix.parse;
+
+module.exports.posix = posix.parse;
+module.exports.win32 = win32.parse;