fix: support D405 stereo module for sensor options

D405 exposes color stream via "Stereo Module", not "RGB Camera".
Fall back to Stereo Module when RGB Camera is not found.

src/lerobot/cameras/realsense/camera_realsense.py

@@ -341,15 +341,24 @@ class RealSenseCamera(Camera):
         return self._async_read(timeout_ms=10000, read_depth=read_depth)
 
     def _get_color_sensor(self) -> "rs.sensor":
-        """Returns the color sensor from the active pipeline profile."""
+        """Returns the sensor that controls the color stream.
+
+        Most RealSense cameras expose "RGB Camera" for color. The D405 has no
+        separate RGB module — its color stream comes from "Stereo Module".
+        We try RGB Camera first, then fall back to Stereo Module.
+        """
         if self.rs_profile is None:
             raise RuntimeError(f"{self}: rs_profile must be initialized before use.")
 
         device = self.rs_profile.get_device()
-        for sensor in device.query_sensors():
+        sensors = {s.get_info(rs.camera_info.name): s for s in device.query_sensors()}
-            if sensor.get_info(rs.camera_info.name) == "RGB Camera":
+
-                return sensor
+        for name in ("RGB Camera", "Stereo Module"):
-        raise RuntimeError(f"{self}: no RGB Camera sensor found on device.")
+            if name in sensors:
+                return sensors[name]
+
+        available = list(sensors.keys())
+        raise RuntimeError(f"{self}: no color sensor found. Available sensors: {available}")
 
     def _configure_sensor_options(self) -> None:
         """Applies manual sensor options (exposure, gain, white balance) to the color sensor.