feat: initialize WiFiSense - WiFi Signal Intelligent Analysis & Envir…

…onment Awareness Engine

- Cross-platform WiFi scanning with graceful degradation to mock scanner
- Signal strength analysis with RSSI statistics, channel congestion, SNR estimation
- Environment fingerprinting with BSSID-based hashing and similarity comparison
- Device tracking with appearance/disappearance/change detection
- Human presence detection with activity level assessment
- Terminal ASCII heatmap and HTML export
- Historical trend analysis with anomaly detection
- Multi-format report export (JSON/CSV/HTML/Markdown)
- Zero external dependencies, pure Python standard library
- 77 unit tests, full type annotations