Modified SPO2 Algorithm
- Extract averaging initialization into spo2_algorithm_init_averaging()
- Add spo2_algorithm_reset_runtime() for runtime reinitialization
- Improve finger detection using AC signal delta threshold comparison
- Fix averaging buffer reset by clearing internal data buffers only
- Standardize SPO2_CONTROL logs to LOG_MODULE_SPO2_ALGORITHM
- Disable WFDB dependency and dataset compile definitions in CMake
- Remove/comment unused WFDB test utilities and includes