feat(field): Field.Input adopts commit-submit on Enter — the text-input family doctrine (A-3.1)

Adoption, not design (audit ficha field F-2, refined against password-field):
the family doctrine is WRITTEN in the password-field morfo — per-keystroke
typing is plain data flow; Enter is the terminal gesture. textarea already
had commit-submit; the base Field.Input did not — the text-input pair was
asymmetric, and the machine flagged the shell as interactive-with-0-events
(A-3.1), converging with the clean-room audit finding "field infra-declarado".

- morfo: scope gains sema; expression family-default (the base shell speaks
  with the family voice — the concrete fields carry the packs); apg textbox
  (the password/textarea cite); commit-submit event (commit.submit, neutral,
  post, target input) + Enter in the Input keyboard contract.
- soma FieldInputProvider: onkeydown — plain Enter (no modifiers), gated on
  disabled/readonly, triggers commit-submit through the runtime.

Verified live in the field demo: Enter stamps data-event="commit-submit" /
family=commit / intent=neutral / phase=active on the input and the demo trace
logs the event. Machine: field -> PASS (A-3.1 + A-1.4 cleared). Field suite
3/3, vocab exit 0, type baseline 57.

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

src/uix/morfo/components/field.ts

@@ -4,12 +4,38 @@ import { v } from '../types';
 export const fieldMorfo = {
 	name: 'Field',
 	kebab: 'field',
-	scope: ['soma', 'eidos'],
+	scope: ['soma', 'sema', 'eidos'],
+	// The base shell stays on the family voice: the concrete fields carry the
+	// packs; Field.Input's Enter submit speaks with the commit family's base
+	// signature (adoption of the written family doctrine — see the event note).
+	expression: 'family-default',
+	// Field.Input is the single-line text input — same pattern the password /
+	// textarea siblings cite.
+	apg: 'https://www.w3.org/WAI/ARIA/apg/patterns/textbox/',
 	texts: {
 		label: '#?components.field.label|Field',
 		'required-indicator': '#?components.field.required-indicator|*',
 		'optional-indicator': '#?components.field.optional-indicator|(optional)'
 	},
+	events: [
+		// User pressed Enter on the plain-text Field.Input. ADOPTION of the
+		// family doctrine written (with incident) in password-field's morfo:
+		// per-keystroke typing is NOT a commit — `commit` is for terminal
+		// actions, and Enter-to-submit IS the text-input pattern (aligned with
+		// password / textarea / editable / number-field / search / combobox).
+		// This closed the text-input pair's asymmetry (audit ficha field F-2:
+		// textarea had `commit-submit`, the base Input did not).
+		{
+			name: 'commit-submit',
+			semantic: {
+				family: 'commit',
+				verb: 'submit',
+				target: v.partRef('input'),
+				intent: 'neutral',
+				sequence: 'post'
+			}
+		}
+	],
 	parts: [
 		{
 			name: 'Provider',
@@ -125,7 +151,8 @@ export const fieldMorfo = {
 					severity: 'optional',
 					condition: { when: 'prop-truthy', prop: 'required' }
 				}
-			]
+			],
+			keyboard: [{ key: 'Enter', action: 'submit' }]
 		},
 		{
 			name: 'HelperText',

src/uix/soma/components/field/field-provider.svelte.ts

@@ -356,6 +356,17 @@ export class FieldInputProvider {
 		this.opts.onValueChange.current(value);
 	};
 
+	/**
+	 * Enter → `commit-submit` (the morfo keyboard contract). Adoption of the
+	 * text-input family doctrine (password-field precedent): typing is plain
+	 * data flow; Enter is the terminal gesture.
+	 */
+	readonly onkeydown = (e: SomaEvent<KeyboardEvent, HTMLInputElement>) => {
+		if (this.provider.isDisabled || this.provider.isReadonly) return;
+		if (e.key !== 'Enter' || e.ctrlKey || e.metaKey || e.altKey || e.shiftKey) return;
+		void this.provider.runtime.trigger('commit-submit');
+	};
+
 	readonly props = $derived.by(() =>
 		this.runtimePart.assert({
 			// Morfo-declared attrs (type, data-state, aria-labelledby, aria-invalid,
@@ -371,7 +382,8 @@ export class FieldInputProvider {
 			// Morfo declares aria-describedby from the helper-text part; soma joins
 			// the helper + error ids, so it overrides with the richer value.
 			'aria-describedby': this.describedBy,
-			oninput: this.oninput
+			oninput: this.oninput,
+			onkeydown: this.onkeydown
 		} as const)
 	);
 }