Rank Candidates

Record scored examples: one routing-memory record each, plus an audit row.

The routing-memory record is written before its audit row for each example, because it is the load-bearing one (the router votes over it) and embedding it can fail; writing the audit row only afterwards means a failed embedding never leaves an orphan audit row.

A failed embedding is a 502 that names the model, not a 500. Every example in the batch is embedded, so this is the call an operator makes most often and the one most likely to meet a misconfigured router_embedding_model.

Score keys are stored canonically as instance:model (see :func:_validated_scores), which is the form the router canonicalizes its candidates to, so how a policy spells a candidate cannot decide whether it matches.