docs: add sponsor section for Warp in README (#5127)

README.md

+<!-- Premium Sponsors -->
+<p align="center"><strong>Special thanks to our sponsor:</strong></p>
+<div align="center">
+  <a href="https://go.warp.dev/memos" target="_blank" rel="noopener">
+    <img src="https://raw.githubusercontent.com/warpdotdev/brand-assets/main/Github/Sponsor/Warp-Github-LG-02.png" alt="Warp" height="256" />
+  </a>
+  <p>
+    <a href="https://go.warp.dev/memos" target="_blank" rel="noopener">Warp is built for coding with multiple AI agents</a>
+  </p>
+</div>
+
 # Memos
 
 <img align="right" height="96px" src="https://raw.githubusercontent.com/usememos/.github/refs/heads/main/assets/logo-rounded.png" alt="Memos" />