Add demand and proposed workplan for Attribute Value Type catalog.

Consumer citation-evidence needs closed value types; ITC-DATA has Attribute
and DataType stubs but no catalog. Track as ITC-WP-0013.

workplans/ITC-WP-0013-attribute-value-type-catalog.md

@@ -0,0 +1,94 @@
+---
+id: ITC-WP-0013
+type: workplan
+title: "Attribute Value Type catalog (Data Model extension)"
+domain: infotech
+repo: info-tech-canon
+status: proposed
+priority: high
+created: "2026-07-30"
+updated: "2026-07-30"
+depends_on_workplans:
+  - ITC-WP-0006
+owner: codex
+spec_refs:
+  - demand/AttributeValueTypes.md
+  - seeds/InfoTechCanonDataModel_RC1_seed.md
+  - ../citation-evidence/wiki/AttributeValueTypes-proposal.md
+---
+
+# ITC-WP-0013 — Attribute Value Type Catalog
+
+## Goal
+
+Turn the demand in `demand/AttributeValueTypes.md` into a **canonical,
+machine-readable catalog of attribute value types** under the Data Model
+(or a tightly coupled standard), so consumers such as citation-evidence share
+stable type ids, encodings, and CodeList cardinality rules.
+
+## Intent
+
+ITC-DATA already owns Attribute / Field / DataType / Representation / CodeList
+but does not close the set of practical value types for structured capture.
+This workplan fills that gap without inventing a parallel “form field”
+universe.
+
+## Tasks
+
+### T01 — Demand intake (PURPOSES)
+
+```task
+id: ITC-WP-0013-T01
+status: todo
+priority: high
+```
+
+Process `demand/AttributeValueTypes.md` under Purpose/Demand (ITC-WP-0006)
+if still required for kernel-adjacent standards; record decision to extend
+ITC-DATA vs new sibling standard.
+
+### T02 — Draft catalog standard
+
+```task
+id: ITC-WP-0013-T02
+status: todo
+priority: high
+depends_on: [T01]
+```
+
+Draft seed standard section or document:
+
+- closed AttributeValueType list (MVP from consumer proposal)
+- wire encoding rules
+- mapping to Representation / CodeList / Constraint
+- out-of-scope rules (email-as-type, etc.)
+
+### T03 — Machine-readable catalog
+
+```task
+id: ITC-WP-0013-T03
+status: todo
+priority: high
+depends_on: [T02]
+```
+
+Add YAML (+ schema) under `infospace/` and register in indexes/validation.
+
+### T04 — Consumer alignment note
+
+```task
+id: ITC-WP-0013-T04
+status: todo
+priority: medium
+depends_on: [T03]
+```
+
+Publish short alignment note for citation-evidence (and future form UIs);
+link from Data Model kernel map.
+
+---
+
+## Out of scope
+
+- Implementing React widgets (citation-evidence CE-WP-0012).
+- Full ISO 11179 tooling.