docs: add demo video and update README

README.md

@@ -45,9 +45,10 @@ tags:
 ## 📺 Demo & Submission
 
 ### 🛠️ Technical Walkthrough
+> **See the "Dual-Brain" architecture in action.** Watch how LifeFlow transforms a vague prompt into a fully optimized itinerary.
 <div align="center">
   <a href="https://www.youtube.com/watch?v=2P0q4jzUuvE" target="_blank">
-    <img src="https://img.youtube.com/vi/2P0q4jzUuvE/maxresdefault.jpg" alt="Watch LifeFlow AI Demo" width="65%" />
+    <img src="https://img.youtube.com/vi/2P0q4jzUuvE/maxresdefault.jpg" alt="Watch LifeFlow AI Demo" width="55%" />
   </a>
   
   <br>