Describe every value kind in one table instead of spreading it over the code

A kind like colour or texture used to be spelled out in five parallel
lists, its port type, its empty value, its glyph, its label and its list
tag - 22 literal places for texture alone. core/properties/kinds.ts now
holds one row per kind and the rest is derived from it, so adding a kind
is one row. The five literal nodes collapse into literals.ts, the six
kind menus into one helper.

Number, Text, Boolean is now the one order everywhere; the variable and
port menus used to list Boolean before Text.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/core/store/serialize.ts

@@ -1,7 +1,6 @@
 // Importing the graph package index is what registers the built-in nodes.
 import {
   createEmptyGraph,
-  DECLARED_PORT_KINDS,
   type DeclaredPort,
   type DeclaredPortKind,
   type Graph,
@@ -15,36 +14,35 @@ import type { Asset, TextureFrame } from '../model/Asset';
 import { isAssetType } from '../model/AssetTypes';
 import { emptyEdit, type InstanceEdit, isEmptyEdit } from '../model/instance';
 import {
-  colorItem,
-  colorItemValue,
   type FieldValue,
-  isTextureItem,
-  textureItem,
-  textureItemValue,
-  isColorItem,
   type PropertyBag,
   type PropertyValue,
   type StructValue,
+  tagOf,
 } from '../model/Properties';
 import { PROJECT_FORMAT_VERSION, type Project } from '../model/Project';
 import type { SceneObject } from '../model/SceneObject';
 import { isTextureFile, normalizeFrameRect } from '../model/texture';
 import { hasParentCycle } from '../model/walk';
-import type { FlatItem } from '../properties/listItems';
+import {
+  DECLARED_PORT_KINDS,
+  FIELD_KINDS,
+  type FieldKind,
+  isTaggedKind,
+  VARIABLE_KINDS,
+  type VariableKind,
+} from '../properties/kinds';
+import { type FlatItem, makeFlatItem } from '../properties/listItems';
 import {
   coerceValue,
   COMMON_PROPS,
-  FIELD_KINDS,
-  type FieldKind,
   isValidFieldName,
   isValidVariableName,
   type PropertyDef,
   type PropertySchema,
   schemaFor,
   type StructFieldDef,
-  VARIABLE_KINDS,
   variableDef,
-  type VariableKind,
 } from '../properties/PropertySchema';
 
 /**
@@ -356,11 +354,11 @@ function asStoredValue(value: unknown): PropertyValue | undefined {
 const isPrimitive = (value: unknown): value is number | string | boolean =>
   typeof value === 'number' || typeof value === 'string' || typeof value === 'boolean';
 
-/** A primitive, or the objects a flat position may hold: a tagged color or texture. */
+/** A primitive, or the one object a flat position may hold: a tagged item. */
 const asFlatItem = (value: unknown): FlatItem | undefined => {
   if (isPrimitive(value)) return value;
-  if (isColorItem(value)) return colorItem(colorItemValue(value));
-  return isTextureItem(value) ? textureItem(textureItemValue(value)) : undefined;
+  const tag = tagOf(value);
+  return tag !== undefined && isTaggedKind(tag) ? makeFlatItem(tag, value as PropertyValue) : undefined;
 };
 
 /** A list item: a flat one, or a struct of flat ones. */