fix: address low-priority coverage and config issues #118-#121

[longieirl]

Summary

• Test coverage: pdf_processing_orchestrator.py lines 23-30 (TYPE_CHECKING guard) #121: Add `if TYPE_CHECKING:` to `exclude_lines` in `pyproject.toml` — eliminates phantom coverage gaps across all 26 TYPE_CHECKING guards in the codebase
• Test coverage: processor.py line 284 (set_duplicate_detection_strategy) #118: Add `test_set_duplicate_strategy_stores_strategy` — covers `processor.py:284`
• Test coverage: processor.py lines 421-422, 469-472 (activity log + template lookup) #119: Add `test_activity_log_called_after_run` and `test_template_registry_lookup_on_transaction_group` — covers `processor.py:421-422` and `469-472`
• Test coverage: extraction_orchestrator.py lines 119-121 (template init failure) #120: Add `test_template_init_failure_falls_back_to_default` — covers `extraction_orchestrator.py:119-121`

Changes

• `pyproject.toml`: add `if TYPE_CHECKING:` to coverage `exclude_lines`
• `tests/test_processor_refactored_methods.py`: new `TestCoverageGaps` class with 3 tests
• `tests/services/test_extraction_orchestrator.py`: 1 new test for template init failure

Type

• Bug fix

Testing

• Tests pass (coverage >= 91%)
• Manually tested
• `make docker-integration` passed locally

Checklist

• Code follows project style
• Self-reviewed
• Documentation updated (if needed)
• No new warnings

Downstream impact

• This PR changes a public interface in `bankstatements_core`

Closes #118, #119, #120, #121