milestone 23: close the remaining codex findings

the vitest "something prevents Vite server from exiting" warning was
@stylexjs/unplugin, not our code: configureServer starts a 150ms polling
interval for HMR and clears it from server.httpServer's close event, which
vitest resolves to null in middleware mode. drop that one hook under VITEST
and keep the transform.

textMuted was swept rather than judged. measured against their grounds, the
39 flat text-zinc-500 sites went 4.12:1 -> 7.56:1 in dark mode, repairing a
WCAG AA failure, so that stands; the 4 already-adaptive sites went 7.40:1 ->
4.62:1 in light mode for nothing, so a textSecondary token restores their
original zinc-600/zinc-400 pair.

append the symbol families to the reset's font stack: Select renders U+25BE
and Segoe UI does not carry it.

correct two acceptance criteria that were literally false: both greps match
only comments.

web/src/features/dashboard/DashboardPage.tsx

@@ -55,7 +55,7 @@ const styles = stylex.create({
 	},
 	periodIdle: {
 		backgroundColor: { default: "transparent", ":hover": colors.surfaceHover },
-		color: colors.textMuted,
+		color: colors.textSecondary,
 	},
 	/** Dynamic: the caller sizes the placeholder to the widget it stands in for. */
 	skeletonHeight: (height: number) => ({ height }),