Add grounded NPC interaction extractor

internal/modules/dnd/extract/npcinteractions/model.go

@@ -0,0 +1,16 @@
+package npcinteractions
+
+type extractionResponse struct {
+	Interactions []interactionResponse `json:"interactions"`
+}
+
+type interactionResponse struct {
+	Name       string                         `json:"name"`
+	Kind       string                         `json:"kind"`
+	SourceRefs []interactionSourceRefResponse `json:"source_refs"`
+}
+
+type interactionSourceRefResponse struct {
+	StartUnitID int `json:"start_unit_id"`
+	EndUnitID   int `json:"end_unit_id"`
+}