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/[id]/page.tsx

@@ -72,7 +72,7 @@ export default async function SessionDetailPage({ params }: { params: Promise<{
 
       <Card className="bp-glass">
         <CardHeader>
-          <CardTitle className="text-base">Intensity timeline</CardTitle>
+          <CardTitle className="text-sm">Intensity timeline</CardTitle>
         </CardHeader>
         <CardContent>
           <SessionTimelineChart timeline={timeline} />
@@ -81,7 +81,7 @@ export default async function SessionDetailPage({ params }: { params: Promise<{
 
       <Card className="bp-glass">
         <CardHeader>
-          <CardTitle className="text-base">Devices</CardTitle>
+          <CardTitle className="text-sm">Devices</CardTitle>
         </CardHeader>
         <CardContent className="flex flex-col gap-1">
           {detail.devices.map((d) => (