Retrieves a list of institutions the user can join. Results are wrapped in a UserInstitution-like structure with nested institution_data and account_data. Visibility rules depend on user account type and allowJoining/account settings. Optionally filters by a search term (matched against name, ainame, or account name).
JWT token passed in x-access-token header
Optional search term to filter institutions by name, ainame, or account name (case-insensitive)
"Biology"