feat: 4 sensing examples — sleep apnea, stress, room environment

examples/sleep/apnea_screener.py — detects breathing cessation
events (>10s), computes AHI score, classifies OSA severity.

examples/stress/hrv_stress_monitor.py — real-time SDNN/RMSSD
from mmWave HR, stress level with visual bar.

examples/environment/room_monitor.py — dual-sensor (CSI + mmWave)
room awareness: occupancy, light, RF fingerprint, activity events.

examples/README.md — index with hardware table and quick start.

Co-Authored-By: claude-flow <ruv@ruv.net>

examples/README.md

@@ -0,0 +1,35 @@
+# Examples
+
+Real-time sensing applications built on the RuView platform.
+
+| Example | Sensors | What It Does |
+|---------|---------|-------------|
+| [Medical: Blood Pressure](medical/) | mmWave (COM4) | Contactless BP estimation from HRV |
+| [Sleep: Apnea Screener](sleep/) | mmWave (COM4) | Detects breathing cessation events, computes AHI |
+| [Stress: HRV Monitor](stress/) | mmWave (COM4) | Real-time stress level from heart rate variability |
+| [Environment: Room Monitor](environment/) | CSI (COM7) + mmWave (COM4) | Occupancy, light, RF fingerprint, activity events |
+
+## Hardware Required
+
+| Port | Device | Cost |
+|------|--------|------|
+| COM7 | ESP32-S3 (WiFi CSI) | ~$9 |
+| COM4 | ESP32-C6 + Seeed MR60BHA2 (60 GHz mmWave) | ~$15 |
+
+## Quick Start
+
+```bash
+pip install pyserial numpy
+
+# Blood pressure
+python examples/medical/bp_estimator.py --port COM4
+
+# Sleep apnea screening
+python examples/sleep/apnea_screener.py --port COM4 --duration 3600
+
+# Stress monitoring
+python examples/stress/hrv_stress_monitor.py --port COM4
+
+# Full room monitor (both sensors)
+python examples/environment/room_monitor.py --csi-port COM7 --mmwave-port COM4
+```