fix(upgrade): add blank lines around changelog in upgrade output

Add a blank line before and after the changelog section in the upgrade
command output for better visual separation from the status/metadata block.

Author: BYK

src/lib/formatters/human.ts

@@ -2282,7 +2282,7 @@ export function formatUpgradeResult(data: UpgradeResult): string {
   // Append changelog if available
   const changelogOutput = formatChangelog(data);
   if (changelogOutput) {
-    return `${result}\n${changelogOutput}`;
+    return `${result}\n\n${changelogOutput}\n`;
   }
 
   return result;