feat(planner): implement C1 weekly planner home screen (#26)

Three-breakpoint layout (mobile/tablet/desktop) with VarietyScoreCard,
WeekStrip, DayMealCard components. Server loads week plan and variety
score via API; read-only role behavior derived from benutzer.rolle.

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

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

@@ -0,0 +1,59 @@
+import { describe, it, expect } from 'vitest';
+import { render, screen } from '@testing-library/svelte';
+import WeekStrip from './WeekStrip.svelte';
+
+const weekStart = '2026-03-30'; // Monday
+
+const slots = [
+	{ id: 's1', slotDate: '2026-03-30', recipe: { id: 'r1', name: 'Pasta', effort: 'Easy' } },
+	{ id: 's2', slotDate: '2026-03-31', recipe: { id: 'r2', name: 'Curry', effort: 'Medium' } }
+];
+
+describe('WeekStrip', () => {
+	it('renders 7 day chips', () => {
+		render(WeekStrip, { props: { weekStart, slots, selectedDay: '2026-03-30', today: '2026-04-03' } });
+		const chips = screen.getAllByRole('button');
+		expect(chips).toHaveLength(7);
+	});
+
+	it('marks today chip with data-today attribute', () => {
+		render(WeekStrip, { props: { weekStart, slots, selectedDay: '2026-03-30', today: '2026-04-03' } });
+		const todayChip = screen.getByTestId('day-chip-2026-04-03');
+		expect(todayChip.getAttribute('data-today')).toBe('true');
+	});
+
+	it('marks selected chip with data-selected attribute', () => {
+		render(WeekStrip, { props: { weekStart, slots, selectedDay: '2026-03-30', today: '2026-04-03' } });
+		const selectedChip = screen.getByTestId('day-chip-2026-03-30');
+		expect(selectedChip.getAttribute('data-selected')).toBe('true');
+	});
+
+	it('shows meal indicator dot for days with a meal', () => {
+		render(WeekStrip, { props: { weekStart, slots, selectedDay: '2026-03-30', today: '2026-04-03' } });
+		const dot = screen.getByTestId('dot-2026-03-30');
+		expect(dot.getAttribute('data-has-meal')).toBe('true');
+	});
+
+	it('shows empty dot for days without a meal', () => {
+		render(WeekStrip, { props: { weekStart, slots, selectedDay: '2026-03-30', today: '2026-04-03' } });
+		// 2026-04-01 has no meal
+		const dot = screen.getByTestId('dot-2026-04-01');
+		expect(dot.getAttribute('data-has-meal')).toBe('false');
+	});
+
+	it('calls onselectDay callback when chip is clicked', async () => {
+		let emitted: string | null = null;
+		render(WeekStrip, {
+			props: {
+				weekStart,
+				slots,
+				selectedDay: '2026-03-30',
+				today: '2026-04-03',
+				onselectDay: (day: string) => { emitted = day; }
+			}
+		});
+		const chip = screen.getByTestId('day-chip-2026-03-31');
+		chip.click();
+		expect(emitted).toBe('2026-03-31');
+	});
+});