Add temperature compensation and webcam mic noise sensing

- Temperature: dynamic compensation using CPU temp (factor=1.85, calibrated for eye1)
- Noise: uses arecord from webcam mic instead of broken MEMS HAT mic
- Config: added sensors section for temp_factor and noise_device
- API: now returns raw_temp and cpu_temp alongside compensated temp

Calibration: 69°F actual ambient
🦊 Christmas Eve 2025

config.example.yaml

@@ -11,6 +11,18 @@ database:
 sampling:
   interval_seconds: 60  # How often to read sensors
 
+sensors:
+  # Temperature compensation factor for CPU heat bleed
+  # Calibrate by comparing raw sensor temp to actual ambient
+  # factor = (cpu_temp - raw_temp) / (raw_temp - actual_temp)
+  # eye1.local calibration: CPU=49.4°C, Raw=30.7°C, Actual=20.6°C → factor=1.85
+  temp_compensation_factor: 1.85
+  
+  # ALSA device for noise sensing (webcam mic)
+  # Use "default" for system default, or specify like "hw:1,0"
+  # Run "arecord -l" to list available devices
+  noise_device: "default"
+
 lcd:
   enabled: true
   brightness: 0.5