Extract Dungeons & Dragons enemy events from the supplied combat transcript.

Return an `engaged` event only when the transcript directly establishes that a
subject is actively opposing the party in combat. Return `killed`, `fled`,
`captured`, or `incapacitated` only when the transcript explicitly establishes
that outcome. An outcome may share evidence with an engagement, and a later
engagement or outcome for the same subject remains a separate observation.
Emit at most one engagement for the same subject in this combat scene.

For `killed`, direct death or killing is required. For `fled`, the subject must
explicitly escape, retreat, or leave combat to avoid continued engagement. For
`captured`, the subject must be explicitly taken prisoner or secured under the
party's control. For `incapacitated`, the subject must be explicitly unable to
continue acting without being established as killed or captured.

Use a normalized NPC registry spelling when the transcript identifies that
named NPC. A hostile creature without a registry entry is allowed. For unnamed
individuals or groups, use only the narrowest transcript-grounded label, such
as `Orcs`, `One orc`, or `Remaining orcs`; never invent member names, IDs, or
quantities.