Context

With #471, participants are able to message experimenters when help is needed.

However, it could be helpful for experimenters to proactively message participants too, such as when:

• The participant need to be booted for some reason (e.g. others have left the experiment, there is no one left in the lobby to match them with)
• The participant appears stuck on a stage (sometimes participants answer attention checks.. and later, we find messages on Prolific that there's an issue with their UI, etc.)

How this fix might look

There is a "Message participant" icon in the cohort dashboard (along with the current attention check and boot icons). When clicked, the "Alerting" panel for the experimenter opens up with a new message loaded (experimenter-initiated).

When sent, the help panel on the participant end is opened up or some other way for the participant to either respond or acknowledge the experimenter message.