feat(client): add eyebrow typography variant and lighter page titles

- Introduce a reusable eyebrow Typography variant in the theme (13px, 500 weight, uppercase, 0.08em tracking) for section headings
- Apply it to ConfigBox titles in /settings and to "Job queue" / "Failed jobs" in /logs
- Drop the page header weight from 600 to 400 with tighter tracking so titles read lighter and more refined

client/src/Components/design-elements/SplitBox.tsx

@@ -63,9 +63,9 @@ export const ConfigBox = ({
 			left={
 				<Stack spacing={theme.spacing(LAYOUT.XS)}>
 					<Typography
-						textTransform={"capitalize"}
 						component="h2"
-						variant="h2"
+						variant="eyebrow"
+						color="text.secondary"
 					>
 						{title}
 					</Typography>