fix(planner): address all PR review blockers

- Fix logic bug `{#if !isPlanner === false}` - view/cook buttons now visible for all roles, swap only for planner
- Convert Tauschen from dead button to link with suggestions href
- Add week.ts unit tests (23 tests covering getWeekStart Sunday edge case, prevWeek/nextWeek, weekDays, isToday, formatWeekRange)
- Fix isToday to use UTC consistently (.toISOString().slice(0,10)) instead of local date
- Add server-side role guard to createPlan action (403 for members)
- Add weekStart format validation in createPlan action
- Add isSelected prop to DayMealCard with green treatment
- Make variety banner sticky on mobile (always visible per spec)
- Add day name abbreviation above date badge in desktop column headers
- Remove placeholder Navigation text from desktop sidebar
- Add aria-label to desktop empty tile buttons
- Add variety score partial failure test, multiple overlaps test, WeekStrip today+selected test

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

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

@@ -0,0 +1,146 @@
+import { describe, it, expect, vi, afterEach } from 'vitest';
+import {
+	getWeekStart,
+	prevWeek,
+	nextWeek,
+	weekDays,
+	isToday,
+	formatWeekRange,
+	formatDayLabel
+} from './week';
+
+describe('getWeekStart', () => {
+	it('returns Monday for a Monday input', () => {
+		// 2026-03-30 is a Monday
+		const d = new Date('2026-03-30T12:00:00Z');
+		expect(getWeekStart(d)).toBe('2026-03-30');
+	});
+
+	it('returns Monday for a Wednesday input', () => {
+		// 2026-04-01 is a Wednesday → week starts 2026-03-30
+		const d = new Date('2026-04-01T12:00:00Z');
+		expect(getWeekStart(d)).toBe('2026-03-30');
+	});
+
+	it('returns Monday for a Sunday input (edge case — goes back 6 days)', () => {
+		// 2026-04-05 is a Sunday → week starts 2026-03-30
+		const d = new Date('2026-04-05T12:00:00Z');
+		expect(getWeekStart(d)).toBe('2026-03-30');
+	});
+
+	it('returns Monday for a Saturday input', () => {
+		// 2026-04-04 is a Saturday → week starts 2026-03-30
+		const d = new Date('2026-04-04T12:00:00Z');
+		expect(getWeekStart(d)).toBe('2026-03-30');
+	});
+
+	it('handles year boundary correctly (Dec 28 2025 → week starts Dec 22 2025)', () => {
+		const d = new Date('2025-12-28T12:00:00Z');
+		expect(getWeekStart(d)).toBe('2025-12-22');
+	});
+});
+
+describe('prevWeek', () => {
+	it('returns the Monday 7 days before', () => {
+		expect(prevWeek('2026-03-30')).toBe('2026-03-23');
+	});
+
+	it('handles month boundary', () => {
+		expect(prevWeek('2026-04-06')).toBe('2026-03-30');
+	});
+
+	it('handles year boundary', () => {
+		expect(prevWeek('2026-01-05')).toBe('2025-12-29');
+	});
+});
+
+describe('nextWeek', () => {
+	it('returns the Monday 7 days after', () => {
+		expect(nextWeek('2026-03-30')).toBe('2026-04-06');
+	});
+
+	it('handles month boundary', () => {
+		expect(nextWeek('2026-03-30')).toBe('2026-04-06');
+	});
+
+	it('handles year boundary', () => {
+		expect(nextWeek('2025-12-29')).toBe('2026-01-05');
+	});
+});
+
+describe('weekDays', () => {
+	it('returns exactly 7 dates', () => {
+		expect(weekDays('2026-03-30')).toHaveLength(7);
+	});
+
+	it('starts on the given weekStart', () => {
+		const days = weekDays('2026-03-30');
+		expect(days[0]).toBe('2026-03-30');
+	});
+
+	it('ends 6 days after weekStart', () => {
+		const days = weekDays('2026-03-30');
+		expect(days[6]).toBe('2026-04-05');
+	});
+
+	it('has consecutive daily dates', () => {
+		const days = weekDays('2026-03-30');
+		for (let i = 1; i < 7; i++) {
+			const prev = new Date(days[i - 1] + 'T00:00:00Z');
+			const curr = new Date(days[i] + 'T00:00:00Z');
+			expect(curr.getTime() - prev.getTime()).toBe(86400000);
+		}
+	});
+
+	it('handles month boundary correctly', () => {
+		const days = weekDays('2026-03-30');
+		expect(days[1]).toBe('2026-03-31');
+		expect(days[2]).toBe('2026-04-01');
+	});
+});
+
+describe('isToday', () => {
+	afterEach(() => {
+		vi.useRealTimers();
+	});
+
+	it('returns true for today (UTC)', () => {
+		vi.useFakeTimers();
+		vi.setSystemTime(new Date('2026-04-03T10:00:00Z'));
+		expect(isToday('2026-04-03')).toBe(true);
+	});
+
+	it('returns false for yesterday', () => {
+		vi.useFakeTimers();
+		vi.setSystemTime(new Date('2026-04-03T10:00:00Z'));
+		expect(isToday('2026-04-02')).toBe(false);
+	});
+
+	it('returns false for tomorrow', () => {
+		vi.useFakeTimers();
+		vi.setSystemTime(new Date('2026-04-03T10:00:00Z'));
+		expect(isToday('2026-04-04')).toBe(false);
+	});
+});
+
+describe('formatWeekRange', () => {
+	it('returns a non-empty string', () => {
+		expect(formatWeekRange('2026-03-30')).toBeTruthy();
+	});
+
+	it('contains both start and end month info', () => {
+		const range = formatWeekRange('2026-03-30');
+		// Start is March 30, end is April 5 — range should span both months
+		expect(range).toContain('–');
+	});
+});
+
+describe('formatDayLabel', () => {
+	it('returns a non-empty string', () => {
+		expect(formatDayLabel('2026-03-30')).toBeTruthy();
+	});
+
+	it('contains a comma separator', () => {
+		expect(formatDayLabel('2026-03-30')).toContain(',');
+	});
+});