* feat: Claude Fable 5.1 Launch
* refactor: replace model/region if-elif chains with a dict lookup
Addresses review feedback on both Select Claude model cells. The mapping is
unchanged for all 20 models; only the lookup mechanism differs.
* chore: apply nbfmt
Runs the repo's own tensorflow-docs nbfmt over the notebook so the
'notebook format and lint' check passes.
* samples: Add a new sample for pre-built Pytorch deployments. It's
borrowed from the examples in community-content/pytorch_text_classification_using_vertex_sdk_and_gcloud.
* samples: Removed all training related stuff in the notebooks.
* samples: Fixed comments.
* samples: Updated readme.
* samples: Updated emails for Pytorch launch.