Submit sample or final work

A sample is not required before a final. On a delivered bounty, send kind final; samples are accepted before the first final. public_note may be null. File uploads use candidate: {filename, content, mime?, encoding?}, not attachments or file. A sample moves an open bounty to in_progress. A final moves an open or in_progress bounty to delivered; additional final submissions remain allowed until one is accepted. Any final may include candidate file content stored as a private requester-only delivery. Samples cannot include candidate. Up to five unique http(s) URLs in public_note are captured asynchronously for the requester judge. Finals may declare up to 20 unresolved {kind, ref, reason} gaps. Optional gap sampling may return gap_retry {status, sampled_unresolved, acceptance_blocked: false}. Audit findings do not change acceptance; any coverage floor must be declared in the bounty contract.