test(transcribe): prove Delete fires once via real shape + action (#327)

Review follow-up (Sara): the prior single-owner evidence was two separate
unit facts against an inert DOM stub. This renders a real AnnotationShape,
attaches the live transcribeShortcuts action, focuses the region, and presses
Delete once — asserting deleteCurrentRegion fires exactly once. A genuine
integration guard against re-introducing a double-bind.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/document/annotation/AnnotationShape.svelte.spec.ts

@@ -2,9 +2,32 @@ import { describe, it, expect, vi, afterEach } from 'vitest';
 import { cleanup, render } from 'vitest-browser-svelte';
 import { page } from 'vitest/browser';
 import AnnotationShape from './AnnotationShape.svelte';
+import {
+	transcribeShortcuts,
+	type TranscribeShortcutOptions
+} from '$lib/shared/actions/transcribeShortcuts';
 
 afterEach(cleanup);
 
+function noopShortcutOptions(
+	overrides: Partial<TranscribeShortcutOptions> = {}
+): TranscribeShortcutOptions {
+	return {
+		isPanelOpen: () => true,
+		isCheatsheetOpen: () => false,
+		panelMode: () => 'edit',
+		goToNextRegion: () => {},
+		goToPrevRegion: () => {},
+		toggleMode: () => {},
+		closePanel: () => {},
+		startDrawMode: () => {},
+		toggleTrainingMark: () => {},
+		deleteCurrentRegion: () => {},
+		openCheatsheet: () => {},
+		...overrides
+	};
+}
+
 function makeAnnotation(id = 'ann-1') {
 	return {
 		id,
@@ -128,4 +151,29 @@ describe('AnnotationShape', () => {
 
 		expect(onfocus).toHaveBeenCalledOnce();
 	});
+
+	// Integration: a real rendered shape + the live transcribeShortcuts action.
+	// Pressing Delete on the focused region must delete exactly once — proving the
+	// action is the single owner and the shape contributes no competing handler.
+	it('with the transcribeShortcuts action active, Delete deletes the focused region exactly once', () => {
+		const deleteCurrentRegion = vi.fn();
+		render(AnnotationShape, {
+			annotation: makeAnnotation(),
+			isHovered: false,
+			isActive: true,
+			showDelete: true,
+			onclick: () => {},
+			onpointerenter: () => {},
+			onpointerleave: () => {}
+		});
+
+		const annotationEl = page.getByTestId('annotation-ann-1').element() as HTMLElement;
+		const action = transcribeShortcuts(annotationEl, noopShortcutOptions({ deleteCurrentRegion }));
+
+		annotationEl.focus();
+		annotationEl.dispatchEvent(new KeyboardEvent('keydown', { key: 'Delete', bubbles: true }));
+
+		expect(deleteCurrentRegion).toHaveBeenCalledTimes(1);
+		action.destroy();
+	});
 });