Return the interactions array even when no interaction is established. Every
record must contain name, kind, and source_refs. Cite transcript ranges that
support both the NPC identity and the interaction kind.

Use exactly one kind per occurrence:

- mentioned: the NPC is referred to but is not established as present or communicating;
- noncombat_presence: the NPC is present and relevant but does not meaningfully participate in dialogue or combat;
- dialogue: the NPC speaks, responds, or is directly engaged in a meaningful non-combat exchange;
- combat_ally: the NPC actively participates in combat on the party's side;
- combat_opponent: the NPC actively participates in combat against the party; or
- other: the transcript clearly establishes a direct NPC occurrence that fits none of the preceding kinds.

When activities overlap, active combat participation outranks dialogue,
presence, and mention; dialogue outranks noncombat presence and mention; and
noncombat presence outranks mention. Other is only for directly evidenced
activity outside those categories. Split an occurrence rather than assigning
both combat alignments.