[BUG] Top-level semantica import fails due to circular import between pipeline_builder and pipeline_validator

## Summary After fixing the missing `Type` import in `semantica/utils/helpers.py`, top-level `import semantica` fails because the package eagerly imports the pipeline module, which has a circular import between `pipeline_builder.py` and `pipeline_validator.py`. ## Environment - OS: Windows - Python: 3.12 - Package: semantica - Installed version reported by pip: 0.0.5 ## Reproduction ```bash python -m venv .venv312 .venv312\Scripts\activate pip install semantica python -c "import semantica" ``` Note: this appears after resolving the earlier missing `Type` import issue. ## Actual Result ```text ImportError: cannot import name 'Pipeline' from partially initialized module 'semantica.pipeline.pipeline_builder' (most likely due to a circular import) ``` The chain is approximately: ```text semantica/__init__.py -> semantica/pipeline/__init__.py -> execution_engine.py -> failure_handler.py -> pipeline_builder.py -> pipeline_validator.py -> pipeline_builder.py ``` ## Expected Result `import semantica` should succeed without circular import errors. ## Why This Matters Even when users only need concrete modules like: ```python from semantica.ingest import FileIngestor from semantica.split import StructuralChunker from semantica.semantic_extract import NERExtractor ``` the top-level package import fails first because `semantica/__init__.py` eagerly imports pipeline components. ## Suggested Fix Avoid eager pipeline imports in `semantica/__init__.py`, or refactor the circular dependency between `pipeline_builder.py` and `pipeline_validator.py`. A lower-risk short-term option would be to lazy-load optional top-level exports so unrelated modules remain usable even if pipeline orchestration has an import issue.