Relax private D&D response schemas

docs/internal/modules.md

@@ -192,6 +192,12 @@ decodes the model response, assigns the generic source identity to every source
 reference, canonicalizes duplicate references, orders spell casts by their
 earliest cited unit, and returns `dnd.SpellList`.
 
+Its private response schema admits only the structural transport envelope:
+required fields, JSON types, array and object shapes, and unknown-field
+rejection. It maps integer source-unit candidates directly without repairing
+semantic values, so the deterministic shape, catalog, and source-reference
+validators own blank values, empty evidence, and invalid or unresolved ranges.
+
 The extractor owns its private model-response DTO, embedded prompt, LLM response
 schema, strict option decoder, injected shared LLM client, and prompt/schema
 manifest metadata. During preparation it resolves the optional `spell_catalog`
@@ -250,6 +256,11 @@ registry slot. Its prompt and private response schema are package-owned. The
 prompt follows the shared D&D extraction ordering and cache policy documented
 in [LLM Runtime](llm.md#dd-extraction-prompt-ordering-and-cache-boundaries).
 
+The private response schema owns only structural transport validation and maps
+integer source-unit candidates unchanged. Required semantic content, non-empty
+evidence, and valid source ranges are rejected by the deterministic shape and
+source-reference validators.
+
 ### `internal/modules/dnd/extract/combatturns`
 
 The combat extractor prepares one structured request per supplied chunk using