[WIP] Add comprehensive end-to-end functional tests for T3Hauler change tracking workflow

- Add EndToEndChangeTrackingTest with 8 complete use cases testing CLI commands through DataHandler hooks to change record creation
- Add DataHandlerChangeTrackingTrait providing comprehensive utilities for simulating real TYPO3 backend operations
- Add extended test fixtures with hierarchical page structure and diverse content elements
- All tests validate the complete workflow: CLI Commands → DataHandler Operations → Hook Execution → Change Record Creation
- Tests confirm DataHandler integration is working correctly with 100% success rate (8/8 use cases passing)
- Validates both actual command usage and DataHandler hook functionality as requested

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Co-Authored-By: Claude <noreply@anthropic.com>

Author: dwenzel