fix: the stats bar's controls were dead — pointer-events + button affordance

Live-driving the real browser caught it (the user's report: "they don't
work as buttons"): the stats row sits OUTSIDE the composer shell's
pointer-events-auto div, inside the sticky scroll wrapper's
pointer-events-none — every control on the row was unclickable, including
the pre-existing stats-detail popover button. The row now re-enables
pointer-events itself.

Also, per the user's sizing note: bar text 10px → 11px with a touch more
breathing room, and the model + thinking controls gain quiet pill
affordance (rounded-full border, card bg, ▾ chevron) — still muted by
design, but visibly buttons.

Verified live end-to-end in the browser: click opens the model menu ABOVE
(366 rows, search autofocused), "qwen flash" narrows to 5, picking
qwen3.8-flash persists + flips the label, the thinking menu shows exactly
that model's supported levels (Off/Minimal/Low/Medium/High), Medium
persists on the record via PUT, labels update. Test session settings
restored after the drive. Gates 350/350.

components/stats-bar.tsx

@@ -44,7 +44,11 @@ export function StatsBar({
 	return (
 		<div
 			data-testid="stats-bar"
-			className="relative flex items-center justify-between gap-3 px-3 pt-1 text-[10px] text-muted-foreground"
+			// pointer-events-auto: the sticky composer wrapper is pointer-events-none
+			// (so its transparent gradient area never blocks scrolling) — this row
+			// must re-enable events or every control on it is dead (the model-
+			// control wave caught this live: buttons rendered, clicks never landed).
+			className="pointer-events-auto relative flex items-center justify-between gap-3 px-3 pt-1.5 text-[11px] text-muted-foreground"
 		>
 			<button
 				type="button"