Interface ReadbackPlan

ordered filled-cell indices to read aloud, each named by its grid address ("row 1, column 2") in the UI. The FIRST goodCells are the SOUND SAMPLE (the required read-back of §15.5); the remainder are the other filled cells the authenticator MAY optionally keep reading for extra coverage past the milestone (§14.4 "climb as far as you like"). Reading past the sample adds coverage of the actual value — never less soundness.

the milestone: how many leading cells form the sound sample. Reading this many reaches NO-DIFFERENCE (affirmative); the ceremony does NOT end there — the user reads on through cells or presses Done. Equals cells.length for an all-cells plan (sample == everything).

how many of the SOUND SAMPLE cells were appended purely for §14.5 homoglyph compensation (counted within goodCells).