refactor(build): align dependencies with updated ECG feature extraction API
- update dependency revisions for csv_process, wfdb_process, and ecg_feature_extraction
- link against library targets instead of package targets
- make demo executable optional via LIB_DEMO_ENABLE
- migrate to updated WFDB reader member names
- update ECG feature extraction API usage and R-peak flag naming
- initialize lead count before feature extraction
- simplify respiration test setup and align test cases with API changes