[Portal] Fix Transactions link in Archived Documentation section

Update the Transactions link to point to /engine instead of /wallets/server/send-transactions.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: eabdelmoneim

apps/portal/src/app/page.tsx

@@ -96,7 +96,7 @@ function ArchiveSection() {
         />
         <ArticleCardIndex
           description="Transactions knowledge base and guides"
-          href="/wallets/server/send-transactions"
+          href="/engine"
           icon={ArchiveIcon}
           title="Transactions"
           external