Redesign: special handle for cairo-lang

[mazurroman]

This issue is for @melnikga who is already familiar with the matter.

Create a new url /cairo-lang that will render the app for integration into the cairo-lang.org website. This means:

• Full screen (no ability to exit fullscreen)
• No k-bar
• No light mode
• Different logo / header text according to figma design

[melnikga]

I'll take this