Add D&D location normalizer

internal/modules/dnd/normalize/locations/assets/prompts/task.md

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+Review location candidates and cited transcript context. Group candidates only
+when the evidence clearly identifies one physical place.
+
+Do not group candidates solely because their names match, their evidence is
+nearby, one place is nested inside another, or their labels are generic. Keep
+parent and child places, similarly named places, and uncertain aliases
+separate. For an accepted group, select the supplied candidate with the
+clearest established display name as canonical.