Even though I trust you, there's no way anyone can guarantee that a hacker won't get into your database and get my proprietary source code.

I'm no security expert but one way I can think of is creating an encryption system which works like this: all my source code will be stored encrypted on your (non-ephemeral) databases. The decryption key will be stored on my computer, and it'll be transferred to the server when I run Kite and destroyed as soon as I quit Kite. The key will be stored in your server only in an ephemeral storage (in-memory database etc.)