fix(pointing): Temp layer threading protection.

[petejohanson]

• Ensure all layer operations occur on the system work queue thread.

Fixes: #2719

PR check-list

• Branch has a clean commit history
• Additional tests are included, if changing behaviors/core code that is testable.
• Proper Copyright + License headers added to applicable files (Generally, we stick to "The ZMK Contributors" for copyrights to help avoid churn when files get edited)
• Pre-commit used to check formatting of files, commit messages, etc.
• Includes any necessary documentation changes.

[jhorology]

Thank you for your response. It seems that the problem wasn't just about threading. Take a look at the following code.

https://github.com/petejohanson/zmk/blob/d6d4cfb88c031bf640dd82646447b2d2b57e4769/app/src/pointing/input_processor_temp_layer.c#L104-L108

If the layer is deactivated due to other factors during the active period, temp_layer_state#is_activate will not be turned off and the layer will not be activated again.