feat: convert demo video to GIF for autoplay

- Convert MP4 to GIF (981KB, optimized)
- GIF autoplays and loops by default in GitHub
- Update README to use image tag instead of video tag
- Remove original MP4 file

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

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

Author: User

README.md

@@ -76,9 +76,7 @@ ACE enables agents to learn from execution feedback-what works, what doesn't, an
 
 Watch ACE learn from its own mistakes in real-time! This demo shows how ACE handles the infamous "seahorse emoji problem" - a challenge where LLMs often hallucinate that a seahorse emoji exists (it doesn't).
 
-<video src="kayba_test_demo.mp4" width="100%" autoplay loop muted>
-  <a href="kayba_test_demo.mp4">Watch the demo</a>
-</video>
+![Kayba Test Demo](kayba_test_demo.gif)
 
 In this example:
 - **Round 1**: The agent incorrectly provides 🐴 (horse emoji)