fix(ios pwa): force masthead safe-area inline + detect standalone + bump SW
The PWA kept serving a stale shell so the env-based fix never reached it. Now: detect
standalone explicitly (larger Dynamic-Island fallback), set --ios-safe-top AND force the
masthead padding inline (survives a stale cached stylesheet), re-apply after htmx chrome
swaps. Bumped the service worker cache (v11 -> v12) so the PWA refreshes.