### Why a domain column currently differs from its authored value.
###
### Diagnostic-only derived state. Projection decisions never read this enum;
### the planner recomputes from authored facts and schema, then rewrites the
### reason with the final domain value. Because it is singular, it records the
### terminal stage that selected that value.
enum: CrdtProjectionReason
serialized: byIndex
values:
  ### The attempted parent target is hidden or missing and FK projection set
  ### the column to null.
  - foreignKeySetNull
  ### The attempted parent target is hidden or missing and FK projection set
  ### the column to the default value.
  - foreignKeySetDefault
  ### The attempted parent target is hidden or missing and FK projection cannot
  ### repair the value, so the row is hidden while the attempt is preserved.
  - foreignKeyMissingParent
  ### A visible unique-index loser received a deterministic conflict-free value.
  - uniqueConflict
  ### A hidden row was released from a unique index so visible rows can claim it.
  - hiddenUniqueRelease