Add security hardening and bias-t support

Security improvements:
- Add interface name validation to prevent command injection
- Fix XSS vulnerability in pager message display
- Add security headers (X-Content-Type-Options, X-Frame-Options, etc.)
- Disable Werkzeug debug PIN
- Add security documentation

Features:
- Add bias-t power support for SDR dongles across all modes

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

routes/sensor.py

@@ -114,11 +114,13 @@ def start_sensor() -> Response:
         builder = SDRFactory.get_builder(sdr_device.sdr_type)
 
         # Build ISM band decoder command
+        bias_t = data.get('bias_t', False)
         cmd = builder.build_ism_command(
             device=sdr_device,
             frequency_mhz=freq,
             gain=float(gain) if gain and gain != 0 else None,
-            ppm=int(ppm) if ppm and ppm != 0 else None
+            ppm=int(ppm) if ppm and ppm != 0 else None,
+            bias_t=bias_t
         )
 
         full_cmd = ' '.join(cmd)