fix(recipes): address review feedback — shared type, design system tokens, test coverage

- Extract RecipeSummary type to $lib/recipes/types.ts (was duplicated in 3 files)
- Fix +page.svelte header link: replace Skeleton UI classes with design system tokens
- Fix h1: use font-[var(--font-display)] and correct size
- Fix FilterChipRow: text-[11px] → text-[13px] + tracking-[0.04em] per design system
- Fix RecipeCard metadata: text-[11px] → text-[12px] for readability
- Remove unused imports (vi, beforeEach, afterEach) from page.test.ts
- Add combined search + effort filter test
- Add reset-to-Alle filter test

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

frontend/src/routes/(app)/recipes/page.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { describe, it, expect } from 'vitest';
 import { render, screen } from '@testing-library/svelte';
 import { userEvent } from '@testing-library/user-event';
 import Page from './+page.svelte';
@@ -71,4 +71,29 @@ describe('recipe library page', () => {
 		render(Page, { props: { data: { recipes: [] } } });
 		expect(screen.getByText(/keine rezepte/i)).toBeInTheDocument();
 	});
+
+	it('applies search and effort filter together', async () => {
+		const user = userEvent.setup();
+		render(Page, { props: { data: mockData } });
+
+		await user.click(screen.getByRole('button', { name: 'Leicht' }));
+		const searchInput = screen.getByPlaceholderText(/suchen/i);
+		await user.type(searchInput, 'Gemüse');
+
+		expect(screen.getByText('Gemüsesuppe')).toBeInTheDocument();
+		expect(screen.queryByText('Spaghetti Bolognese')).not.toBeInTheDocument();
+		expect(screen.queryByText('Chicken Curry')).not.toBeInTheDocument();
+	});
+
+	it('resets to all recipes when Alle chip is clicked', async () => {
+		const user = userEvent.setup();
+		render(Page, { props: { data: mockData } });
+
+		await user.click(screen.getByRole('button', { name: 'Mittel' }));
+		expect(screen.queryByText('Spaghetti Bolognese')).not.toBeInTheDocument();
+
+		await user.click(screen.getByRole('button', { name: 'Alle' }));
+		expect(screen.getByText('Spaghetti Bolognese')).toBeInTheDocument();
+		expect(screen.getByText('Chicken Curry')).toBeInTheDocument();
+	});
 });