fix: Clean up Rust warnings and add Python vital signs detection

Rust changes:
- Fix unused variable warnings in wifi-densepose-nn (densepose.rs, inference.rs, tensor.rs, translator.rs)
- Remove unused imports in wifi-densepose-mat (breathing.rs, pipeline.rs, csi_receiver.rs, debris_model.rs, vital_signs_classifier.rs)
- All tests continue to pass

Python changes:
- Add vital_signs.py module with BreathingDetector and HeartbeatDetector classes
- Mirror Rust wifi-densepose-mat detection functionality
- Update v1 package version to 1.2.0
- Export new vital signs classes from core module

v1/src/__init__.py

@@ -29,7 +29,7 @@ Author: WiFi-DensePose Team
 License: MIT
 """
 
-__version__ = "1.1.0"
+__version__ = "1.2.0"
 __author__ = "WiFi-DensePose Team"
 __email__ = "team@wifi-densepose.com"
 __license__ = "MIT"