Register item registry normalization

docs/integrations/dnd-item-registry-artifacts.md

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+# D&D Item Registry Artifact
+
+This contract defines the durable, source-grounded item registry produced by
+`dnd/item-registry`. It records transcript-established item types and unique
+designations for one source document; it is not an inventory, holder record,
+quantity ledger, or item-occurrence artifact.
+
+## Identity and compatibility
+
+| Property | Value |
+| --- | --- |
+| Artifact kind | `dnd/item-registry` |
+| Schema ID | `notarius.dnd.item_registry` |
+| Schema name | `notarius_dnd_item_registry_v1` |
+| Schema version | `v1` |
+| Media type | `application/json` |
+| Identity policy | `dnd.item_registry.identity.v1` |
+
+`v1` accepts one strict JSON object with required `items`; the array may be
+empty. Item and source-reference objects reject unknown fields. An incompatible
+artifact shape or identity-policy change uses a new version or policy.
+
+## Wire shape and identity
+
+Each item has these required fields:
+
+| Field | Contract |
+| --- | --- |
+| `id` | `item:sha256:` followed by 64 lowercase hexadecimal characters. |
+| `name` | Non-empty transcript-established item type or unique designation. |
+| `source_refs` | One or more transcript evidence ranges that establish the item. |
+
+A source reference has exactly `source_id`, `start_unit_id`, and `end_unit_id`.
+The source ID identifies the transcript, unit IDs are positive inclusive unit
+identifiers, and the start may not follow the end.
+
+```json
+{
+  "items": [
+    {
+      "id": "item:sha256:31e73b6280ef98e4d8070e07fd4de9b2c3e842cc03af1a09ca631cb95b73e3b3",
+      "name": "Star Compass",
+      "source_refs": [
+        {"source_id": "session-7", "start_unit_id": 4, "end_unit_id": 5}
+      ]
+    }
+  ]
+}
+```
+
+The ID is deterministic for an item name or type, rather than for one physical
+instance. Notarius normalizes the display name for comparison with Unicode
+NFKC, supported apostrophe normalization, collapsed whitespace, and case
+folding. It hashes compact JSON for this array:
+
+```text
+["dnd.item_registry.identity.v1", comparison_name]
+```
+
+The canonical ID is the lowercase SHA-256 digest of those bytes with the
+`item:sha256:` prefix. Equal comparison names represent one item identity;
+normalization unions their transcript evidence when it safely consolidates a
+candidate group.
+
+## Scope, reconciliation, and evidence
+
+The registry includes named unique items, concrete reusable item types, stable
+unique designations, and separately established currency denominations. It
+excludes vague loot or treasure, generic weapons, quantities, inferred
+properties, and inferred uniqueness. Capitalization alone does not establish
+eligibility.
+
+Normalization first applies deterministic display, evidence, and ID rules. It
+then may use a bounded LLM-assisted proposal to reconcile semantically duplicate
+records. The proposal may choose only a supplied candidate display name;
+invalid, uncertain, overlapping, or unsafe proposals retain the deterministic
+result with retry or fallback diagnostics. Currency denominations, materially
+different item types, and merely nearby objects remain distinct. Source
+references establish registry provenance, not evidence for later artifacts.
+
+## Publication
+
+The registry is a selectable D&D artifact. See
+[Configuration](../config.md#production-module-keys) for module keys and
+validator chains, and the [JSON output contract](json-output.md) for
+publication. It does not yet define a consumer handoff contract.