Feature Request: Make cronSchedule editable during template deployment

When a Railway template includes a cronSchedule in its railway.json, users cannot modify it during deployment. This forces template authors to either hardcode a schedule or omit it entirely.

Request: Allow users to edit the cronSchedule value during template deployment, similar to how environment variables work.

Use case: Backup services need flexible scheduling - some users want hourly backups, others daily or weekly. Currently, it is impossible to provide a sensible default while allowing customization.

Previously asked in this form:

https://station.railway.com/questions/template-deployment-with-cron-schedule-in-08c09af5