fix: Snapshot camera timestamps on the physics thread for ground truth accuracy

[Arcod7]

• Capture simulation time on the physics thread when the camera pose is committed, instead of relying on the GL thread. This ensures ground truth timestamps match the actual pose used for rendering.
• Introduce a three-stage handoff (tempCaptureTime_ -> pendingCaptureTime_ -> captureTime_) in OpenGLView to safely pass the timestamp across thread boundaries to all camera types.
• Expose Camera::getLastCaptureTime() so consumers can retrieve the simulation time of the last delivered frame.
• Multibeam2 bypasses Camera::UpdateTransform() so its implemented again.
• Thread safety relies on drawingQueueMutex: the physics thread writes tempCaptureTime_ inside UpdateDrawingQueue, and the render thread reads it in PerformDrawingQueueCopy under the same mutex.

Without the fix	With the fix

In this example, I'm building an Octomap from a Depth Camera, but Stonefish was giving me late timestamps for the Depth Camera. This caused a misalignment between the depth camera point cloud and the odometry pose, resulting in a distorted map (left). With the fix, timestamps match the actual pose commit, so the point cloud is correctly registered (right).