Unify card title size to text-sm

Several CardTitle usages were text-base while others were already
text-sm, giving section headers inconsistent sizes across pages.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BuWtppPBizG2NQRa31FCRa

app/(app)/sessions/page.tsx

@@ -24,7 +24,7 @@ export default async function SessionsPage({
       </div>
       <Card className="bp-glass">
         <CardHeader>
-          <CardTitle className="text-base">History</CardTitle>
+          <CardTitle className="text-sm">History</CardTitle>
         </CardHeader>
         <CardContent className="flex flex-col gap-3">
           <SessionsTable sessions={sessions} />