fix(boot): a stylesheet lost on the way is asked for again

A lost stylesheet left the page unstyled until a reload, and every e2e step that finds elements by
testid still passed on it. Only axe noticed: the one-off target-size failure on eight scattered
controls. Losing the main stylesheet on purpose gives those same eight.

frontend/src/watchMain.tsx

@@ -5,6 +5,7 @@ import WatchPage from "./watch/WatchPage";
 import { T } from "./watch/watchStrings";
 import "./index.css";
 import { installStaleBuildReload } from "./lib/staleBuild";
+import { retryLostStylesheets } from "./lib/stylesheetRetry";
 
 // The entry of a public /watch/<token> link (watch.html). Whoever opens it got the link from a
 // friend: signed out, often on a phone, often on mobile data — so it imports the player page and
@@ -14,6 +15,8 @@ import { installStaleBuildReload } from "./lib/staleBuild";
 
 // A tab left open across a release reloads onto the new build instead of failing on a chunk.
 installStaleBuildReload();
+// A stylesheet lost on the way is asked for again rather than leaving the page unstyled.
+retryLostStylesheets();
 
 const crashCopy = () => ({ title: T.crashTitle, subtitle: T.crashHint, reload: T.reload });