fix(purchase): carry the no_submission proof to the root row when every account of a fan-out was refused #1844

Follow-up from the review of #1842 (#682 P0).

On a multi-account run, #1842 sets NoSubmission only on a refused account's own row (executeForAccountLate, before saveAccountRow). The root row still ends one of two ways:

• failed without NoSubmission, when every account failed: summarizeFanOut returns errAllAccountsFailed as a plain error, so saveTerminalExecution never sees the before-submission class;
• partially_completed, when another account bought.

Effects, both in the safe direction (under-buy, or a human resolves it):

• Ramp. ListPlanCommittedTx takes the max per identity across root and account rows, so the unflagged root keeps counting the refused account's recs.
• Ladder. A ladder tranche's chain starts at the root execution, so a refused fan-out tranche stays fired with "failed without a no_submission proof".
• Suppressions. The root row keeps its suppressions.

Scope if we want the proof on the root: when every account ended refused before submission, the root should carry the class through summarizeFanOut. Skipped accounts and credential-failure accounts need the same treatment, so a mix of refused and skipped accounts still counts as nothing submitted.

Part of #682.