release: prepare v4.2.0 with GLiNER integration

Version Updates:
- Bump version to 4.2.0 in __about__.py and setup.py
- Add comprehensive CHANGELOG.MD entry for v4.2.0

Major Features in v4.2.0:
- GLiNER integration with 32x performance improvement over spaCy
- Smart cascading engine (regex → GLiNER → spaCy)
- Enhanced CLI with --engine flags for model management
- New nlp-advanced extra for GLiNER dependencies
- 19 new test cases with comprehensive coverage

This release significantly expands DataFog's NER capabilities while
maintaining the lightweight core architecture and backward compatibility.

Author: sidmohan0

CHANGELOG.MD

@@ -1,5 +1,89 @@
 # ChangeLog
 
+## [2025-05-29]
+
+### `datafog-python` [4.2.0]
+
+#### Major Features
+
+- **GLiNER Integration**: Added modern Named Entity Recognition engine with GLiNER (Generalist Model for NER)
+  - New `gliner` engine option in TextService providing 32x performance improvement over spaCy
+  - PII-specialized model support (`urchade/gliner_multi_pii-v1`) for enhanced accuracy
+  - Custom entity type configuration for domain-specific detection
+  - Automatic model downloading and caching functionality
+
+- **Smart Cascading Engine**: Introduced intelligent multi-engine approach
+  - New `smart` engine that progressively tries regex → GLiNER → spaCy
+  - Configurable stopping criteria based on entity count thresholds
+  - Optimized for best accuracy/performance balance (60x average speedup)
+
+- **Enhanced CLI Model Management**: Extended command-line interface
+  - `--engine` flag support for `download-model` and `list-models` commands
+  - GLiNER model discovery and management capabilities
+  - Unified model management across spaCy and GLiNER engines
+
+#### Architecture Improvements
+
+- **Optional Dependencies**: Added new `nlp-advanced` extra for GLiNER dependencies
+  - `pip install datafog[nlp-advanced]` for GLiNER + PyTorch + Transformers
+  - Maintained lightweight core architecture (<2MB)
+  - Graceful degradation when GLiNER dependencies unavailable
+
+- **Engine Ecosystem**: Expanded from 3 to 5 annotation engines
+  - `regex`: 190x faster, structured PII detection (core only)
+  - `gliner`: 32x faster, modern NER with custom entities
+  - `spacy`: Traditional NLP, comprehensive entity recognition
+  - `smart`: Cascading approach for optimal accuracy/speed
+  - `auto`: Legacy regex→spaCy fallback
+
+#### Performance & Quality
+
+- **Validated Performance**: Comprehensive benchmarking across all engines
+  - GLiNER: 32x faster than spaCy with superior NER accuracy
+  - Smart cascading: 60x average speedup with highest accuracy scores
+  - Regex: Maintained 190x performance advantage
+
+- **Comprehensive Testing**: Added 19 new test cases for GLiNER integration
+  - Full coverage of GLiNER annotator functionality
+  - Graceful degradation testing for missing dependencies
+  - Smart cascading logic validation
+  - Cross-engine integration testing
+
+#### Documentation & Developer Experience
+
+- **Updated Documentation**: Comprehensive guides and examples
+  - README performance comparison table with all 5 engines
+  - Engine selection guidance with use case recommendations
+  - GLiNER model management and CLI usage examples
+  - Installation options for different dependency combinations
+
+- **Developer Guide**: Streamlined development documentation
+  - Updated architecture overview with GLiNER integration
+  - Performance requirements and testing strategies
+  - Common development patterns and best practices
+
+#### Breaking Changes
+
+- **Engine Options**: New engine types added to TextService
+  - Existing code using `engine="auto"` continues to work unchanged
+  - New engines `gliner` and `smart` require `[nlp-advanced]` extra
+
+#### Dependencies
+
+- **New Optional Dependencies** (nlp-advanced extra):
+  - `gliner>=0.2.5`
+  - `torch>=2.1.0,<2.7`
+  - `transformers>=4.20.0`
+  - `huggingface-hub>=0.16.0`
+
+#### Migration Guide
+
+For users upgrading from v4.1.1:
+- All existing functionality remains unchanged
+- To use GLiNER: `pip install datafog[nlp-advanced]`
+- Smart cascading: `TextService(engine="smart")` for best balance
+- CLI: Use `--engine gliner` flag for GLiNER model management
+
 ## [2025-05-05]
 
 ### `datafog-python` [4.1.1]

datafog/__about__.py

@@ -1 +1 @@
-__version__ = "4.1.1"
+__version__ = "4.2.0"

setup.py

@@ -5,7 +5,7 @@
     long_description = f.read()
 
 # Use a single source of truth for the version
-version = "4.1.1"
+version = "4.2.0"
 
 project_urls = {
     "Homepage": "https://datafog.ai",