style(git-diff): remove bold from line counts

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/app/src/components/git-diff-pane.tsx

@@ -323,13 +323,13 @@ const styles = StyleSheet.create((theme) => ({
   },
   additions: {
     fontSize: theme.fontSize.sm,
-    fontWeight: theme.fontWeight.semibold,
+    fontWeight: theme.fontWeight.normal,
     color: theme.colors.palette.green[400],
     fontFamily: "monospace",
   },
   deletions: {
     fontSize: theme.fontSize.sm,
-    fontWeight: theme.fontWeight.semibold,
+    fontWeight: theme.fontWeight.normal,
     color: theme.colors.palette.red[500],
     fontFamily: "monospace",
   },