Add support for dark mode

[bracesproul]

Should include a toggle, and defaults to system.

[girithodu]

@bracesproul Could you assign this to me Brace?

[bracesproul]

Done @girithodu

Looking forward to it!

[bracesproul]

hey @girithodu going to unassign you from this, if you've already started feel free to still put a PR up though!

[Pratham271]

I would like to work on this one, if this is open right now

[bracesproul]

@Pratham271 yes it is!

[Pratham271]

On it @bracesproul

[Pratham271]

@bracesproul I have added the logic and it is working fine but what about the colors of dark theme, do you have something in mind or should I push it.

[silvan-soeters]

@Pratham271 ninjachat's colors are easy on the eyes

[bracesproul]

@Pratham271 the shadcn default dark mode colors would be great

[Pratham271]

okay @bracesproul