Commit one existing builder atomically (#6232 D5). A late refusal leaves
no placement/profile/representation helpers or journal entries behind.
The caller supplies a resolved anchor or resolves it using this transaction's
draft. The latter includes existing UI placement preparation in this same
transaction, without changing its policy or nesting another atomic edit.
Renderer, room and history effects remain with the caller after success.
Commit one existing builder atomically (#6232 D5). A late refusal leaves no placement/profile/representation helpers or journal entries behind. The caller supplies a resolved anchor or resolves it using this transaction's draft. The latter includes existing UI placement preparation in this same transaction, without changing its policy or nesting another atomic edit. Renderer, room and history effects remain with the caller after success.