Propagate actual camera dimensions from setCamera() to worker

After setCamera() opens the device, update the worker's camera_width
and camera_height from the actual frame dimensions rather than relying
on values from enumeration which may be incorrect on Windows.

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

Author: sjmf

kvm_serial/kvm.py

@@ -136,6 +136,13 @@ def _capture_frame(self):
                 try:
                     self.video_device.setCamera(self.video_device_idx)
                     self.camera_initialised = True
+                    # Update dimensions from actual camera output
+                    if hasattr(self.video_device, "camera_width"):
+                        self.camera_width = self.video_device.camera_width
+                        self.camera_height = self.video_device.camera_height
+                        logging.info(
+                            f"Camera actual dimensions: {self.camera_width}x{self.camera_height}"
+                        )
                 except Exception as e:
                     error_msg = f"Failed to initialize camera {self.video_device_idx}: {e}"
                     logging.error(error_msg)