FIX Remove duplicate VBLoRAConfig entry from peft.__all__

[SHAI-Akshay-Tripathi]

Description

peft.__all__ listed "VBLoRAConfig" twice. Duplicate entries in __all__ silently confuse documentation tooling, IDE auto-import, and linters that rely on __all__ to determine the public API surface. It's the only duplicate among the 138 entries.

Changes

1. src/peft/__init__.py — remove the duplicate line.
2. tests/test_public_api.py — new test file with two regression tests:
   • test_all_has_no_duplicates — guards against the same regression recurring.
   • test_all_names_are_importable — verifies every name in __all__ is actually accessible on the package.

Verifying the regression test catches the bug

Per CONTRIBUTING.md, a bug fix should be accompanied by a test that fails on the broken code and passes on the fix:

• On main without the __init__.py change: test_all_has_no_duplicates fails with AssertionError: Duplicate names in peft.__all__: {'VBLoRAConfig': 2}.
• With the fix applied: both tests pass.

How to test

python -m pytest tests/test_public_api.py -v