style(changelog): make entry version headings bigger in settings UI

The in-app changelog viewer rendered each entry's version number at the
same size as body text (text-sm font-medium), so visually there was no
clear anchor for where one release's notes ended and the next began.

Bump the version heading to text-xl font-semibold tracking-tight and
widen the bottom margin so each release reads as a proper section
header.

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

app/src/components/ServerTab/ChangelogPage.tsx

@@ -182,8 +182,8 @@ function ChangelogEntryCard({ entry }: { entry: ChangelogEntry }) {
 
   return (
     <div className="border-b border-border/50 pb-6">
-      <div className="flex items-baseline gap-3 mb-1">
-        <h3 className="text-sm font-medium">{entry.version}</h3>
+      <div className="flex items-baseline gap-3 mb-3">
+        <h3 className="text-xl font-semibold tracking-tight">{entry.version}</h3>
         {entry.date && <span className="text-xs text-muted-foreground">{entry.date}</span>}
         {entry.version === 'Unreleased' && <Badge variant="outline">dev</Badge>}
       </div>