Serve PWA icons from fresh /icons/v2/ URLs with every iOS size

iOS showed a letter tile ('N') when adding to the Home Screen. The live files were fine, but a
reverse proxy in front of the app serves static files with a long cache lifetime (live icon.svg
and sw.js were stale) and iOS remembers a failed icon per URL.

- New versioned URLs no proxy/phone has cached; old paths kept for existing installs
- apple-touch-icon declared at 180/167/152/120 (opaque 8-bit RGB PNGs) for app and dashboard
- 180px icon also listed in both manifests; notification icons and root fallbacks use v2
- Service worker cache bumped

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

app/public/dashboard-setup.html

@@ -6,8 +6,11 @@
 <meta name="apple-mobile-web-app-capable" content="yes">
 <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
 <link rel="manifest" href="/dashboard.webmanifest">
-<link rel="icon" type="image/png" sizes="192x192" href="/icons/dashboard-icon-192.png">
-<link rel="apple-touch-icon" href="/icons/dashboard-apple-touch-icon.png">
+<link rel="icon" type="image/png" sizes="192x192" href="/icons/v2/dashboard-icon-192.png">
+<link rel="apple-touch-icon" sizes="180x180" href="/icons/v2/dashboard-apple-touch-icon-180.png">
+<link rel="apple-touch-icon" sizes="167x167" href="/icons/v2/dashboard-apple-touch-icon-167.png">
+<link rel="apple-touch-icon" sizes="152x152" href="/icons/v2/dashboard-apple-touch-icon-152.png">
+<link rel="apple-touch-icon" sizes="120x120" href="/icons/v2/dashboard-apple-touch-icon-120.png">
 <meta name="apple-mobile-web-app-title" content="Station">
 <link rel="stylesheet" href="/pwa-safe.css">
 <title>Station Dashboard — Create Account</title>