style: prettier on v1.4.25 W3 files

`pnpm format:check` flagged two files touched in the previous W3 +
W3b commits — `src/components/insights/insights-tab-strip.tsx` (the
new tab strip) and `src/lib/charts/x-axis-density.ts` (the rebuilt
tick-density helper). Prettier normalised the Tailwind class-name
ordering and the multi-line function signature; no behaviour change.

src/components/insights/insights-tab-strip.tsx

@@ -149,7 +149,7 @@ export function InsightsTabStrip({
       )}
     >
       <div className="flex items-center gap-2">
-        <div className="flex min-w-0 flex-1 gap-2 overflow-x-auto [scrollbar-width:none] [&::-webkit-scrollbar]:hidden">
+        <div className="flex min-w-0 flex-1 [scrollbar-width:none] gap-2 overflow-x-auto [&::-webkit-scrollbar]:hidden">
           {SECTION_IDS.map((id) => {
             const isActive = activeId === id;
             return (