Add custom prompt to the Phi-3.5 WebGPU sample

[rhelenagh]

Hi!

Your Phi-3.5 WebGPU example is very interesting. I would like to know if it is possible to assign a command prompt to your example. I want to test the model in another area, for this it is necessary to tell the model to perform certain operations in a first message with role 'system' and then the requirements of role type 'user' are based on the previous instructions.

I have not found in the documentation how to assign a prompt.

Thank you for your example and information.

I will be very grateful for your replies.