Document D&D spell normalization behavior

docs/internal/overview.md

@@ -65,8 +65,8 @@ run-local construction closures. Preparation injects shared dependencies and
 constructs input, chunk, validators, ordered lanes, and output before source
 parsing. Production modules use strict construction-time option decoding, and
 LLM-backed modules retain the injected shared client. The D&D family registers
-the canonical `dnd/spell-list` codec, typed spell extractor and validators, and
-kind-specific generic merge and normalize strategies; generic JSON validators
+the canonical `dnd/spell-list` codec, typed spell extractor, normalizer, and
+validators, plus kind-specific generic merge strategies; generic JSON validators
 use the serialized-validation contract. The runner executes lanes through
 private exact-type-checked closures, coordinates extract results independently
 of completion timing, and serializes artifacts only through their codec at
@@ -90,6 +90,7 @@ Configuration. The implemented module packages are:
 | `internal/modules/dnd/spells/catalog` | Embeds and validates the versioned D&D 5e 2014 SRD catalog, composes optional overlays, and provides immutable effective lookup. |
 | `internal/modules/generic/merge/appendorder` | Combines accepted extraction results in chunk order. |
 | `internal/modules/generic/normalize/noop` | Preserves accepted merged output. |
+| `internal/modules/dnd/normalize/spells` | Canonicalizes catalog-backed spell names and exact source references, conservatively collapses duplicate casts, and reports deterministic warnings and independently scoped catalog checkpoint identity. |
 | `internal/modules/generic/output/json` | Encodes manifests, lane payloads, warnings, and rejections as logical JSON files. |
 
 `internal/modules/dnd/shared` owns reusable D&D prompt fragments,