Cache-proof asset URLs and inline iOS touch icon

A reverse proxy in front of the app serves stale copies of static files for hours (live app.js and
sw.js were old next to new HTML). iOS also showed a letter tile (N / S) because its separate
icon download failed.

- HTML pages are served through a versioner: every local script/stylesheet/icon/manifest gets a
  content-hash query (app.js?v=…), so any change is a URL no proxy or phone has cached
- Service worker URL versioned too; SW offline lookups tolerate the query string; cache v15
- The 180px apple-touch-icon is embedded in each page as a data: URI, so the Home Screen icon
  no longer depends on a second network request

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

app/public/sw.js

@@ -4,7 +4,7 @@ self.addEventListener('message', event => {
   if (event.data === 'skipWaiting') self.skipWaiting();
 });
 
-const CACHE = 'weather-v14';
+const CACHE = 'weather-v15';
 
 // App shell cached on install for offline resilience.
 const PRECACHE = [
@@ -101,14 +101,14 @@ self.addEventListener('fetch', event => {
           }
           return response;
         })
-        .catch(() => caches.match(request).then(cached => cached || caches.match('/')))
+        .catch(() => caches.match(request, { ignoreSearch: true }).then(cached => cached || caches.match('/', { ignoreSearch: true })))
     );
     return;
   }
 
   // Cache-first for static assets.
   event.respondWith(
-    caches.match(request).then(cached => {
+    caches.match(request, { ignoreSearch: true }).then(cached => {
       if (cached) return cached;
       return fetch(request).then(response => {
         if (response.ok && (