docs: add sudo to start.sh usage comments and USAGE.md examples

All other docs already reference sudo ./start.sh but the inline usage
comments in start.sh itself and the --help example in USAGE.md were
missing it, which could lead users to run without root privileges.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/USAGE.md

@@ -525,7 +525,7 @@ Example: `INTERCEPT_PORT=8080 sudo ./start.sh`
 ### Production server (recommended)
 
 ```
-./start.sh --help
+sudo ./start.sh --help
 
   -p, --port PORT    Port to listen on (default: 5050)
   -H, --host HOST    Host to bind to (default: 0.0.0.0)
@@ -534,6 +534,8 @@ Example: `INTERCEPT_PORT=8080 sudo ./start.sh`
   --check-deps       Check dependencies and exit
 ```
 
+> **Note:** `sudo` is required for SDR hardware access, WiFi monitor mode, and Bluetooth low-level operations.
+
 `start.sh` auto-detects gunicorn + gevent and runs a production WSGI server with cooperative greenlets — this handles multiple SSE streams and WebSocket connections concurrently without blocking. Falls back to the Flask dev server if gunicorn is not installed.
 
 ### Development server

start.sh

@@ -4,12 +4,14 @@
 # Starts INTERCEPT with gunicorn + gevent for production use.
 # Falls back to Flask dev server if gunicorn is not installed.
 #
+# Requires sudo for SDR, WiFi monitor mode, and Bluetooth access.
+#
 # Usage:
-#   ./start.sh                  # Default: 0.0.0.0:5050
-#   ./start.sh -p 8080          # Custom port
-#   ./start.sh --https          # HTTPS with self-signed cert
-#   ./start.sh --debug          # Debug mode (Flask dev server)
-#   ./start.sh --check-deps     # Check dependencies and exit
+#   sudo ./start.sh                  # Default: 0.0.0.0:5050
+#   sudo ./start.sh -p 8080          # Custom port
+#   sudo ./start.sh --https          # HTTPS with self-signed cert
+#   sudo ./start.sh --debug          # Debug mode (Flask dev server)
+#   sudo ./start.sh --check-deps     # Check dependencies and exit
 
 set -euo pipefail