Show whiteboard laser only while click-and-hold is active

[theg1239]

Problem

The whiteboard laser is currently visible continuously.

Requested behavior

Make the laser appear only while the user is actively clicking and holding, and hide it when the click/hold ends.

Acceptance criteria

• The laser is not visible by default.
• Pressing and holding activates and displays the laser.
• Releasing the click hides the laser immediately.