Polish odds and ends across the report

[soulgalore]

A handful of pages and components escaped earlier refresh passes and now stick out next to the styled tabs around them. Bundling the tail-end pieces together so each one
doesn't have to carry its own PR.

The Coach tab's "Page info", "Technologies used to build the page", "Third-party tools" and the resource-hints sidebar were still rendered as plain bordered tables; they now
use the same iter-group + tile pattern as the rest of the per-page tabs, with technologies as small cards (name, version, confidence pill, category chips) and third-party
tools as category-grouped chip lists.

The help page was a flat wall of headings — readable but heavy. Wrapping it in a .help-page container lets it pick up section dividers, capped line-length, hover-to-show
anchor marks on entries with an id, and styling for the option flags scattered through the doc.

The kbSizeCell table-mixin was emitting raw KB numbers ("234.5") instead of formatted strings, so the size columns on pages.html, toplist.html and assets.html had no units —
the table headings carried "(kb)" but values that exceeded a megabyte still read as "5483.6" instead of "5.2 MB". Switched the mixin to h.size.format() so units travel with
the values.

The toplist's "Quick links" rail was a vertical stack of bordered group-items — the only place left in the report that still used that old component. Replaced with the same
small-pipe-separated nav the per-URL tabs use, dropping the lone surviving consumer of .group-item.active styling.

Web Vitals "warning" pills (TTFB / CLS at the second-tier threshold) read as orange-brown rather than yellow because the warning palette was sitting on Tailwind amber-700
(#b45309). Shifted to yellow-700 (#a16207) — same contrast against the pale background, but the colour now matches what users expect a yellow warning state to look like.

Co-authored-by: Claude Opus 4.7 (1M context) noreply@anthropic.com