Publish immutable event-local Polymarket candidate evidence

[proerror77]

Parent

#314

Change contract

For each explicit market_id whose source is closed and whose source triplet identity has passed the existing authentication policy, publish an event-local, content-addressed, no-clobber candidate data / manifest / _SUCCESS triplet containing only rows that actually exist. The candidate manifest records actual counts, including zero, for all five evidence surfaces and is explicitly an untrusted producer carrier, never a Ready decision.

Acceptance criteria

• Non-Ready source-closed events publish a candidate triplet instead of qualification JSON alone; complete Ready events keep the existing strict v2/v3 path.
• Candidate normalization reuses the existing event-local authenticated segment selection, row extraction, canonical ordering, digesting, and no-clobber publication paths.
• Candidate evidence contains one exact market_id, contract, symbol/window, and Up/Down token pair; a complete sibling cannot fill or alter a partial event.
• All five surface counts are explicit, including zero; missing book/trade/reference/settlement rows are neither synthesized nor inferred from request status.
• Any completion row that is present must satisfy the existing identity/digest contract; contradictory present rows fail closed.
• Actual candidate content and manifest digests are bound into the producer qualification bytes before publication.
• Same-byte replay is Unchanged; conflicting bytes at the same immutable path fail closed.
• Focused tests cover missing one-sided book, trade completion, reference, and settlement; sibling isolation; same-byte replay; and no-clobber conflict.

Blocked by

#318 (merged)

Out of scope

Independent Ready/Partial/Rejected verification, catalog receipts or queries, OSS acquisition/downloader behavior, snapshot/cohort construction, evaluator/MCTS behavior, and deployment.

Merge order

This issue must merge before the candidate verifier issue and #319. It is an independent collector rollback unit.

Focused validation

cargo test -p hft-collector --locked polymarket_evidence_artifact::tests::source_closed_partial_events_publish_candidate_triplets_without_ready
cargo test -p hft-collector --locked polymarket_evidence_artifact::tests::candidate_triplets_are_event_local_and_no_clobber
cargo test -p hft-collector --locked polymarket_research_normalize::tests::candidate_normalization_preserves_zero_missing_surfaces_without_rows

Rollout / rollback impact

No runtime cutover in this issue. Rollback removes candidate publication while leaving the existing complete evidence path unchanged.