Better selfie verification for people without thumbs/hands/limbs/etc

[duogenesis]

One option would be to make selfie verification depend entirely on facial features. This would probably also increase the accuracy of verification using ChatGPT. For example, users could be asked to submit several selfies, with some combination of expressions similar to the ones described in #384. Features that'd work well with ChatGPT are likely:

• Eyes closed vs eyes opened
• Smiling vs frowning
• Tongue poking out vs tongue in
• Teeth showing vs teeth hidden
• Looking up vs looking down