Load benchmark review previews eagerly

The review page's 63 preview frames were lazy, so anything capturing the
page in one pass — a screenshot, a print, a PDF — got empty boxes for
every render below the fold. The page is a local report built from
already-generated markup; deferring the frames saves nothing.

Claude-Session: https://claude.ai/code/session_01P9VnXvg4WT8iJbypKBhTnD

Author: noeltock

scripts/bench.ts

@@ -401,7 +401,7 @@ function renderHtml(specs: Map<string, Spec>, results: Result[]): string {
             .map(
               (r) => `<figure class="prod">
                 <figcaption>${esc(r.producer)}</figcaption>
-                <div class="frame"><iframe sandbox loading="lazy" srcdoc="${escAttr(preparePreview(r.inputHtml))}"></iframe></div>
+                <div class="frame"><iframe sandbox loading="eager" srcdoc="${escAttr(preparePreview(r.inputHtml))}"></iframe></div>
               </figure>`,
             )
             .join('\n')