test(tag): expand TagParentPicker keyboard + excludeIds coverage

ArrowUp wrap-around, Escape close, Enter without selection no-op,
keydown without dropdown no-throw, Enter with active selection
selects, excludeIds filter works, parentId fallback as subtitle.

7 new tests covering ~12 branches.

Refs #496.

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

frontend/src/lib/tag/TagParentPicker.svelte.spec.ts

@@ -199,4 +199,125 @@ describe('TagParentPicker – parent name subtitle', () => {
 		// Only the tag name should appear (no subtitle)
 		await expect.element(page.getByRole('option', { name: 'Haus' })).toBeInTheDocument();
 	});
+
+	it('shows the parentId as subtitle when allTags omits the parent', async () => {
+		mockFetchWithTags([{ id: 't2', name: 'Keller', parentId: 'unknown-parent-id' }]);
+		render(TagParentPicker, { name: 'parentId', allTags: [] });
+
+		const input = page.getByRole('combobox');
+		await input.fill('K');
+		await vi.advanceTimersByTimeAsync(300);
+
+		// When parent not found in allTags, fallback shows the parentId itself
+		await expect.element(page.getByText('unknown-parent-id')).toBeInTheDocument();
+	});
+});
+
+describe('TagParentPicker – keyboard navigation', () => {
+	it('ArrowUp wraps around to last option', async () => {
+		mockFetchWithTags([
+			{ id: 't1', name: 'Haus' },
+			{ id: 't2', name: 'Garten' }
+		]);
+		render(TagParentPicker, { name: 'parentId' });
+
+		const input = page.getByRole('combobox');
+		await input.fill('a');
+		await vi.advanceTimersByTimeAsync(300);
+
+		const el = await input.element();
+		// Without prior arrow-down, ArrowUp from -1 wraps via modular arithmetic
+		el.dispatchEvent(
+			new KeyboardEvent('keydown', { key: 'ArrowUp', bubbles: true, cancelable: true })
+		);
+		await vi.advanceTimersByTimeAsync(0);
+
+		expect(el.getAttribute('aria-activedescendant')).toBeTruthy();
+	});
+
+	it('Escape closes the dropdown', async () => {
+		mockFetchWithTags([{ id: 't1', name: 'Haus' }]);
+		render(TagParentPicker, { name: 'parentId' });
+
+		const input = page.getByRole('combobox');
+		await input.fill('H');
+		await vi.advanceTimersByTimeAsync(300);
+
+		const el = await input.element();
+		el.dispatchEvent(
+			new KeyboardEvent('keydown', { key: 'Escape', bubbles: true, cancelable: true })
+		);
+		await vi.advanceTimersByTimeAsync(0);
+
+		// Listbox should be gone
+		expect(document.querySelector('[role="listbox"]')).toBeNull();
+	});
+
+	it('Enter without active selection does nothing', async () => {
+		mockFetchWithTags([{ id: 't1', name: 'Haus' }]);
+		render(TagParentPicker, { name: 'parentId' });
+
+		const input = page.getByRole('combobox');
+		await input.fill('H');
+		await vi.advanceTimersByTimeAsync(300);
+
+		const el = await input.element();
+		el.dispatchEvent(
+			new KeyboardEvent('keydown', { key: 'Enter', bubbles: true, cancelable: true })
+		);
+		await vi.advanceTimersByTimeAsync(0);
+
+		// Hidden input should still be empty
+		expect(hiddenInput('parentId')?.value).toBe('');
+	});
+
+	it('keydown with no active dropdown is a no-op', async () => {
+		render(TagParentPicker, { name: 'parentId' });
+
+		const input = page.getByRole('combobox');
+		const el = await input.element();
+		expect(() =>
+			el.dispatchEvent(new KeyboardEvent('keydown', { key: 'ArrowDown', bubbles: true }))
+		).not.toThrow();
+	});
+
+	it('Enter with active selection selects the highlighted tag', async () => {
+		mockFetchWithTags([
+			{ id: 't1', name: 'Haus' },
+			{ id: 't2', name: 'Garten' }
+		]);
+		render(TagParentPicker, { name: 'parentId' });
+
+		const input = page.getByRole('combobox');
+		await input.fill('a');
+		await vi.advanceTimersByTimeAsync(300);
+
+		const el = await input.element();
+		el.dispatchEvent(new KeyboardEvent('keydown', { key: 'ArrowDown', bubbles: true }));
+		await vi.advanceTimersByTimeAsync(0);
+		el.dispatchEvent(new KeyboardEvent('keydown', { key: 'Enter', bubbles: true }));
+		await vi.advanceTimersByTimeAsync(0);
+
+		// Some tag selected
+		expect(hiddenInput('parentId')?.value).toBeTruthy();
+	});
+});
+
+describe('TagParentPicker – excludeIds filter', () => {
+	it('filters out tags whose id is in excludeIds', async () => {
+		mockFetchWithTags([
+			{ id: 't1', name: 'Haus' },
+			{ id: 't2', name: 'Keller' }
+		]);
+		render(TagParentPicker, { name: 'parentId', excludeIds: ['t1'] });
+
+		const input = page.getByRole('combobox');
+		await input.fill('a');
+		await vi.advanceTimersByTimeAsync(300);
+
+		// Only Keller should be visible
+		const options = document.querySelectorAll('[role="option"]');
+		expect(options.length).toBe(1);
+		expect(options[0].textContent).toContain('Keller');
+	});
 });