fix(planner): exclude current recipe from swap suggestions

Adds excludeRecipeId prop to SwapSuggestionList so the meal being
replaced is not offered as a swap candidate.

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

frontend/src/lib/planner/SwapSuggestionList.test.ts

@@ -74,6 +74,20 @@ describe('SwapSuggestionList', () => {
 		expect(screen.getByTestId('swap-empty-state')).toBeTruthy();
 	});
 
+	it('excludes the recipe being replaced when excludeRecipeId is provided', () => {
+		render(SwapSuggestionList, { props: { ...baseProps, excludeRecipeId: 'r2' } });
+		expect(screen.queryByText('Chicken stir-fry')).toBeNull();
+		expect(screen.getByText('Quick carbonara')).toBeTruthy();
+		expect(screen.getByText('Mushroom risotto')).toBeTruthy();
+	});
+
+	it('shows all recipes when excludeRecipeId is not provided', () => {
+		render(SwapSuggestionList, { props: baseProps });
+		expect(screen.getByText('Quick carbonara')).toBeTruthy();
+		expect(screen.getByText('Chicken stir-fry')).toBeTruthy();
+		expect(screen.getByText('Mushroom risotto')).toBeTruthy();
+	});
+
 	it('disables all Wählen buttons when isLoading is true', () => {
 		render(SwapSuggestionList, { props: { ...baseProps, isLoading: true } });
 		const buttons = screen.getAllByRole('button', { name: /Wählen/i });