Unit tests with network calls cause flaky failures (504 timeouts)

[timenick]

Problem

Several test files under tests/unit/ make real network calls to HuggingFace Hub, causing flaky CI failures when HF is slow or unavailable (e.g., 504 Gateway Timeout).

Affected files

1. tests/unit/eval/test_text_classification.py — Every test instantiates TextDataset which calls datasets.load_dataset() to download GLUE/MRPC from HuggingFace Hub.

2. tests/unit/loader/test_hf_model_class_mapping.py — TestResolveTaskAndModelClass (9 tests) and TestConflictScenarios (5 tests) call AutoConfig.from_pretrained() which downloads model configs from HuggingFace Hub. These were missed in Move misplaced integration/e2e tests out of tests/unit/ #95 which moved the TestHFModelClassMappingE2E class but left the AutoConfig.from_pretrained() callers behind.

Impact

• Unit tests should be fast, deterministic, and offline
• Network failures cause spurious test failures (observed: HfHubHTTPError: 504 Server Error)
• Slows down the unit test suite unnecessarily

Fix

Move these tests to tests/integration/ where network-dependent tests belong.