Support callable filters in TransformerBridge.add_hook()

[jlarson4]

Description

add_hooks functionality had the necessary wiring to exist in TransformerBridge, but was not properly configured to be usable.

- TransformerBridge.add_hook()now accepts a callable filter(str) -> boolas thenameparameter, matching theHookedTransformer` API

• When a callable is passed, the hook is added to every hook point whose name satisfies the filter
• This was already supported in run_with_hooks() but missing from add_hook(), causing AttributeError when migrating notebooks that use filter-based hook registration (e.g. Attribution Patching Demo)
• Adds 4 regression tests covering forward/backward callable filters, string names, and empty matches

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have not rewritten tests relating to key interfaces which would affect backward compatibility