Add support for files API endpoints (#184)

* Add support for files API endpoints

* Apply suggestions from code review

Co-authored-by: Aron Carroll <aron@replicate.com>

* Remove prepareInputs in favor of FileEncodingStrategy

This allows the user to determine if file uploads, falling back to
base64 should be used or just sticking to one approach.

The tests have been updated to validate the file upload payload and
to ensure the url is correctly passed to the prediction create method.

* Remove replicate.files API

* Tell Biome to ignore .wrangler directory

---------

Co-authored-by: Aron Carroll <aron@replicate.com>