added mobile demo link to readme

Author: Shubbu03

README.md

@@ -169,3 +169,4 @@ Mobile-specific build and device instructions live in
 - [Pitch Deck](https://canva.link/1exbqmsqvqn4g8w)
 - [Pitch Deck Video](https://drive.google.com/file/d/1hlA2pwGX64Pkw3hUy8dkAFKloSccGesj/view?usp=sharing)
 - [App Demo](https://drive.google.com/file/d/1ysAksMwu3PFd39oMeOfMPzr4iNCHW2P3/view?usp=sharing)
+- [Mobile Demo](https://youtu.be/w2F-M4NhFEM)