Ask Tabby in the Source Code Browser should include the current file as default context

[Sma1lboy]

Describe the bug

Currently, the logic for the Ask Tabby button exists on each endpoint/files/ page. It might be a good idea to add the current file/directory context to Ask Tabby. The intuition is that people would primarily focus on the current page you're viewing.

We cannot see the connection between Ask Tabby and the current page in the current version

[Sma1lboy]

#3729