CLEAN-01: remove pre-existing unused imports flagged by flake8 F401

[longieirl]

Problem

Running flake8 across packages/parser-core/ and packages/parser-free/ reports numerous pre-existing F401 (unused import) warnings across test files. These were not introduced by any recent PR but have accumulated over time.

Files affected

• tests/patterns/test_credit_card_duplicate_strategy.py — pytest
• tests/services/test_duplicate_detector.py — pytest
• tests/services/test_service_registry.py — pytest
• tests/services/test_sorting_service.py — pytest
• tests/services/test_transaction_type_classifier.py — TemplateProcessingConfig
• tests/test_processor.py — json, MagicMock, Mock, pytest
• tests/test_processor_refactored_methods.py — MagicMock, call, mock_open
• tests/adapters/test_pdfplumber_adapter.py, tests/analysis/, tests/config/, tests/extraction/, tests/domain/, tests/test_*.py — various

Fix

Remove all unused imports from the affected test files and ensure flake8 passes cleanly on both packages.