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/list.d.ts

@@ -0,0 +1,60 @@
+declare namespace list {
+  type List = {
+    /**
+     * Safely splits comma-separated values (such as those for `transition-*`
+     * and `background` properties).
+     *
+     * ```js
+     * Once (root, { list }) {
+     *   list.comma('black, linear-gradient(white, black)')
+     *   //=> ['black', 'linear-gradient(white, black)']
+     * }
+     * ```
+     *
+     * @param str Comma-separated values.
+     * @return Split values.
+     */
+    comma(str: string): string[]
+
+    default: List
+
+    /**
+     * Safely splits space-separated values (such as those for `background`,
+     * `border-radius`, and other shorthand properties).
+     *
+     * ```js
+     * Once (root, { list }) {
+     *   list.space('1px calc(10% + 1px)') //=> ['1px', 'calc(10% + 1px)']
+     * }
+     * ```
+     *
+     * @param str Space-separated values.
+     * @return Split values.
+     */
+    space(str: string): string[]
+
+    /**
+     * Safely splits values.
+     *
+     * ```js
+     * Once (root, { list }) {
+     *   list.split('1px calc(10% + 1px)', [' ', '\n', '\t']) //=> ['1px', 'calc(10% + 1px)']
+     * }
+     * ```
+     *
+     * @param string separated values.
+     * @param separators array of separators.
+     * @param last boolean indicator.
+     * @return Split values.
+     */
+    split(
+      string: string,
+      separators: readonly string[],
+      last: boolean
+    ): string[]
+  }
+}
+
+declare const list: list.List
+
+export = list