morfo: add `archetype` field — cross-layer part categorization

First step toward making morfo articulate the three layers (soma, sema,
eidos) instead of just serving soma. Archetype is a small canonical
vocabulary that lets a part declare its conceptual role beyond its
component-specific kebab name.

Articulation purpose:
- Eidos can style transversally — `[data-archetype=trigger] { ... }`
  applies to every Trigger across all 60+ components without enumeration.
- Sema can map archetypes to canonical action verbs (`trigger` may fire
  `activate`, `item` may fire `select`).
- Docs can categorize parts cross-component for discovery.

The "2-of-3 rule" justifies the extension: at least two layers consume it.

Vocabulary
24 archetypes covering the common cross-component roles:
  provider, trigger, content, overlay, viewport, item, option, indicator,
  thumb, track, label, title, description, close, action, header, image,
  fallback, arrow, separator, group, input, segment, preview.

Designed to stay small. New archetype only added when at least two
existing components share the role. Genuinely-unique parts (Slider.Range,
PinInput.Segment) omit the field.

Implementation
- `MorfoPart.archetype?: MorfoArchetype` — optional union type.
- `ARCHETYPE_VOCABULARY` exported as `as const satisfies` array for
  enumeration tooling.
- `partShallowSchema` (sium validator) gets `archetype: optional(union(...))`.
- MorfoRuntime caches `partMeta` in PartRegistration so `partProps` can
  read `archetype` without re-walking the morfo tree per render.
- `runtime.partProps(part)` emits `data-archetype="..."` when declared.
  Static identity (never mutates), so it ships through partProps not
  through `dom.apply` — Svelte renders it once on first paint.

Tests
2 new tests:
- partProps emits data-archetype when morfo declares one (inline test
  morfo to avoid coupling to catalog state).
- partProps omits data-archetype when not declared (Toggle, pre-catalog).

Verification
- 22/22 runtime tests green.
- svelte-check unchanged at 155.
- No morfo currently declares archetype yet — catalog pass follows in the
  next commit. All existing morfos remain valid (field is optional).

src/uix/morfo/schema.ts

@@ -44,8 +44,10 @@ import type {
 	MorfoPrimitiveValueSource,
 	MorfoValueSource,
 	MorfoCondition,
-	MorfoElement
+	MorfoElement,
+	MorfoArchetype
 } from './types';
+import { ARCHETYPE_VOCABULARY } from './types';
 
 // ── Leaf schemas ──────────────────────────────────────────────────────────
 
@@ -101,6 +103,14 @@ const severitySchema = union(
 
 const partKindSchema = union(literal('public'), literal('virtual'));
 
+const archetypeSchema = union(
+	...(ARCHETYPE_VOCABULARY.map((archetype) => literal(archetype)) as [
+		ReturnType<typeof literal<string>>,
+		ReturnType<typeof literal<string>>,
+		...ReturnType<typeof literal<string>>[]
+	])
+) as Schema<MorfoArchetype, MorfoArchetype>;
+
 // ── MorfoValueSource (tagged union) ───────────────────────────────────────
 
 const primitiveValueSourceSchema = discriminated('kind', [
@@ -261,6 +271,7 @@ const focusSchema = object({
 const partShallowSchema = object({
 	name: string(),
 	kebab: string(),
+	archetype: optional(archetypeSchema),
 	kind: partKindSchema,
 	defaultElement: elementSchema,
 	role: optional(string()),

src/uix/morfo/types.ts

@@ -334,6 +334,86 @@ export interface MorfoFocus {
 	restore?: boolean;
 }
 
+// ── Archetypes ────────────────────────────────────────────────────────────
+
+/**
+ * Cross-component part archetypes — a small canonical vocabulary that lets
+ * a part declare its conceptual role beyond its component-specific kebab.
+ *
+ * Articulation purpose:
+ * - **Eidos** can style transversally: `[data-archetype=trigger] { ... }`
+ *   applies to every Trigger across all components without enumeration.
+ * - **Sema** can map archetypes to canonical action verbs (a `trigger` may
+ *   fire `activate`, an `item` may fire `select`).
+ * - **Docs** can categorize parts cross-component for discovery.
+ *
+ * Not all parts fit an archetype — when a part is genuinely unique to its
+ * component (e.g. `Slider.Range`, `PinInput.Segment`), omit the field. The
+ * runtime emits `data-archetype="..."` on the part's element only when set.
+ *
+ * The vocabulary is intentionally small and stable. Add a new archetype
+ * only when at least two existing components share the role.
+ */
+export type MorfoArchetype =
+	| 'provider' // root context provider
+	| 'trigger' // activates an action or opens an overlay
+	| 'content' // primary content panel of an overlay or section
+	| 'overlay' // modal/dim backdrop behind content
+	| 'viewport' // scrollable / focusable container
+	| 'item' // list / tree / menu item
+	| 'option' // selectable option in a select-like list
+	| 'indicator' // visual progress / decorative state
+	| 'thumb' // draggable handle (slider, scroll, switch)
+	| 'track' // background of slider / scroll / progress
+	| 'label' // text label associated with a control
+	| 'title' // overlay or section title
+	| 'description' // secondary descriptive text
+	| 'close' // dismiss / close button
+	| 'action' // call-to-action button
+	| 'header' // section header (often above content)
+	| 'image' // <img>-based content
+	| 'fallback' // shown when primary content unavailable
+	| 'arrow' // pointer arrow (tooltip / popover)
+	| 'separator' // visual divider
+	| 'group' // grouping container for related items
+	| 'input' // form input element
+	| 'segment' // discrete sub-input (pin-input segment, OTP digit)
+	| 'preview'; // file / link / data preview
+
+/**
+ * Canonical archetype vocabulary as a runtime array. Used by the schema
+ * validator and by tooling that needs to enumerate archetypes.
+ *
+ * Keep in sync with the `MorfoArchetype` type above — order doesn't matter
+ * but every union member must appear.
+ */
+export const ARCHETYPE_VOCABULARY = [
+	'provider',
+	'trigger',
+	'content',
+	'overlay',
+	'viewport',
+	'item',
+	'option',
+	'indicator',
+	'thumb',
+	'track',
+	'label',
+	'title',
+	'description',
+	'close',
+	'action',
+	'header',
+	'image',
+	'fallback',
+	'arrow',
+	'separator',
+	'group',
+	'input',
+	'segment',
+	'preview'
+] as const satisfies readonly MorfoArchetype[];
+
 // ── Part ──────────────────────────────────────────────────────────────────
 
 /**
@@ -351,6 +431,19 @@ export interface MorfoPart {
 	 * Unique across the whole morfo (no nested path namespacing).
 	 */
 	kebab: string;
+	/**
+	 * Cross-component part archetype. Lets eidos style "all triggers" or
+	 * "all overlays" with a transversal selector (`[data-archetype=trigger]`),
+	 * lets sema associate canonical action verbs with a part role, and lets
+	 * docs categorize parts across the catalog.
+	 *
+	 * Optional — omit when the part has no clean cross-component analogue
+	 * (e.g. `Slider.Range` is unique to Slider). When present, the runtime
+	 * emits `data-archetype="..."` on the part's DOM element via `partProps`.
+	 *
+	 * See `ARCHETYPE_VOCABULARY` for the canonical set.
+	 */
+	archetype?: MorfoArchetype;
 	/** Public API part vs internal coordinator (see `MorfoPartKind`). */
 	kind: MorfoPartKind;
 	/**

src/uix/soma/morfo/runtime.svelte.test.ts

@@ -173,6 +173,52 @@ describe('createMorfoRuntime', () => {
 		})
 		cleanup()
 	})
+
+	it('emits data-archetype in partProps when the morfo part declares one', () => {
+		// Inline a tiny morfo with an archetype so the test doesn't depend on
+		// the catalog state of any real component.
+		const archetypedMorfo = {
+			name: 'Probe',
+			kebab: 'probe',
+			scope: ['soma'],
+			parts: [
+				{
+					name: 'Provider',
+					kebab: 'provider',
+					archetype: 'trigger',
+					kind: 'public',
+					defaultElement: 'button',
+					optional: false,
+					data: [],
+					aria: []
+				}
+			]
+		} as const
+		const { result, cleanup } = withEffectRoot(() => {
+			const r = createMorfoRuntime(archetypedMorfo, { dom })
+			r.registerPart('provider', { id: state('p-1') })
+			return r
+		})
+
+		const props = result.partProps('provider')
+		expect(props['data-archetype']).toBe('trigger')
+		expect(props.id).toBe('p-1')
+		expect(props['data-probe']).toBe('')
+		cleanup()
+	})
+
+	it('omits data-archetype when the part does not declare one (default)', () => {
+		// Toggle's morfo has no archetype declared yet (until the catalog pass).
+		const { result, cleanup } = withEffectRoot(() => {
+			const r = createMorfoRuntime(toggleMorfo, { dom })
+			r.registerPart('provider', { id: state('t-1') })
+			return r
+		})
+
+		const props = result.partProps('provider')
+		expect(props['data-archetype']).toBeUndefined()
+		cleanup()
+	})
 })
 
 // ── trigger(eventName) ──────────────────────────────────────────────────────

src/uix/soma/morfo/runtime.svelte.ts

@@ -146,6 +146,8 @@ interface PartRegistration {
 	attachment: RefAttachment | undefined;
 	states: SourceMap | undefined;
 	props: SourceMap | undefined;
+	/** Cached part metadata so `partProps` doesn't re-walk the morfo tree. */
+	meta: MorfoPart;
 }
 
 function readBindings(
@@ -196,7 +198,8 @@ export function createMorfoRuntime(
 			ref: opts.ref,
 			attachment: undefined,
 			states: opts.states,
-			props: opts.props
+			props: opts.props,
+			meta: partMeta
 		};
 
 		if (opts.ref) {
@@ -229,6 +232,10 @@ export function createMorfoRuntime(
 			id: reg.id.current
 		};
 		if (marker) props[marker] = '';
+		// `data-archetype` is part of static identity (cross-component
+		// classification, never mutates), so it ships through partProps —
+		// not through dom.apply. Eidos reads it via `[data-archetype=trigger]`.
+		if (reg.meta.archetype) props['data-archetype'] = reg.meta.archetype;
 		if (reg.attachment) Object.assign(props, reg.attachment);
 
 		return props;