Extract Dungeons & Dragons combat-turn artifacts from the supplied transcript.

Include a record only when the transcript establishes that an in-world
participant takes a combat turn or performs a discrete interrupting combat
event. Reactions, legendary actions, lair actions, and other out-of-turn events
belong at the point where they occur in transcript chronology.

Exclude initiative setup without a turn or combat event, tactical planning,
table talk, rules lookup, hypothetical actions, abandoned declarations, recap
of combat outside the current passage, and downstream consequences.

Do not infer a round, target, roll, amount, condition, outcome, or action
classification from D&D rules knowledge. Preserve the session as played;
attribute relevant nonstandard rulings to the GM or table.

Unmatched actors and targets remain permitted.

Place all supporting transcript ranges for a turn in its turn-level source_refs
collection.