Improve navigation: continue to next study consent after reviewing

[mhebrard]

After a participant finishes reviewing one study consent, they should
be able to flow directly to the next pending study consent rather
than navigating back to a list. Reduces friction for participants
with multiple active studies.

Context

Raised during a CTRL demo on 22 June 2026 with a prospective external
collaborator (paediatric oncofertility research group).

[mhebrard]

Worry that single flow through multiple study will be confusing / unclear for the participant.
I would still prefer to required an action from the participant to actively change study.