A journal save now records no training contribution. A contribution is a second
consent: the privacy page states consent version training-consent-v1 and the
receipt (contribution id, included fields, never-included fields) before the
confirm control is enabled, the receipt is queued on this device only and copies
no photo bytes, note text, or symptom answers, and withdrawal keeps a tombstone
naming every derived artifact by contribution id. Delete-all clears the receipts
with the ledger.
Closes#24