Per-field capability pins that override source truth for writable, searchable, sortable, and required-on-insert. scalarType is observe-only in this release (no manual type pin). Requires assertion rows: include entityFieldSelections on create, or use a dataset with an existing selection baseline. Legacy all-fields datasets must supply the owning entityId per override group. Omitted properties defer to catalog reconciliation. On PUT, replaces the full override set. Sending entityFieldPermissions without entityFieldOverrides rebuilds every writable pin from permissions alone and drops writable pins set here, so re-send entityFieldOverrides alongside any permissions change you want them to survive. searchable, sortable, and requiredOnInsert pins are unaffected by permissions-only requests.
