integrate Pan-Tompkins pipeline and modular ECG feature extraction framework
- Added EcgFeatures module integration into build system
- Added pan_tompkins dependency using FetchContent
- Enabled GoogleTest and CTest infrastructure
- Linked pan_tompkins-lib into ECG feature extraction library
- Added EcgFeatures.cpp and EcgFeatures.h to source tree
- Refactored ECG processing flow into reusable EcgFeatures class
- Added streaming multi-lead ECG sample buffering
- Added deterministic ECG extraction initialization workflow
- Added lead buffer management and sampling rate handling
- Added ECG signal window extraction and PTU segmentation logic
- Added integrated Pan-Tompkins QRS detection support
- Added real-time R-peak detection processing pipeline
- Added ECG feature summary extraction and reporting
- Added ClinicalECGEngine integration hooks
- Added waveform segmentation utilities for PQRST analysis
- Added ECG sample accessor APIs and signal state tracking
- Reduced debug console noise by disabling verbose printf traces
- Updated WFDB processing workflow and annotation debugging
- Added extended annotation and rhythm analysis experiments
- Improved modularity for embedded and DSP-oriented execution
- Preserved deterministic signal-processing behavior
- Maintained compatibility with WFDB-based datasets