Operator-entered single item, parsed by the same rules as LOS ingest (app_data.collateral). Body is one flat item: assetType, an identity field (externalRef, or the asset type's configured identity source key), and value; any other keys are stored as asset attributes subject to the asset type's mapping. A card already ACTIVE-pledged anywhere is rejected. Requires CREATE_COLLATERAL_PLEDGE.

Every pledge is created locked. When the tenant has an external lock provider turned on (collateral-external-lock-provider, e.g. COLLECTORS), the graded card is first locked in the Collectors vault (only the card being added - cards the loan already holds are not re-sent); a refusal is a 400 and nothing is written. A graded card with no collectors_id attribute is rejected in that case, because it can't be locked.