✨ feat(nutriphi): prepare for production release with tests and improved UX

- Remove broken header links to non-existent settings/profile pages
- Replace header links with settings page link
- Remove TODO comments for credit system in analysis controller
- Add comprehensive error handling with German messages in meals store
- Add loading states, retry buttons, and error displays in UI components
- Create new settings page with daily goals editor
- Add 99 tests across backend, web, and shared packages:
  - Backend: MealService, GoalsService, StatsService, FavoritesService,
    RecommendationsService, nutrition.utils (Jest)
  - Web: API client tests with mocks (Vitest)
  - Shared: utility function tests (Vitest)
- Set up test infrastructure (Jest for NestJS, Vitest for SvelteKit)

apps/nutriphi/packages/shared/src/utils/utils.spec.ts

@@ -0,0 +1,189 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import {
+	calculateProgress,
+	sumNutrition,
+	formatNutrient,
+	getProgressColor,
+	detectDeficiencies,
+	suggestMealType,
+	formatDateForDisplay,
+	isToday,
+} from './index';
+
+describe('Shared Utils', () => {
+	describe('calculateProgress', () => {
+		it('should calculate progress with default values', () => {
+			const nutrition = { calories: 1000, protein: 25, carbohydrates: 137, fat: 39 };
+			const progress = calculateProgress(nutrition);
+
+			expect(progress.calories.current).toBe(1000);
+			expect(progress.calories.target).toBe(2000);
+			expect(progress.calories.percentage).toBe(50);
+		});
+
+		it('should use custom goals', () => {
+			const nutrition = { calories: 1500, protein: 75 };
+			const goals = {
+				dailyCalories: 3000,
+				dailyProtein: 150,
+				dailyCarbs: 300,
+				dailyFat: 100,
+			} as any;
+
+			const progress = calculateProgress(nutrition, goals);
+
+			expect(progress.calories.target).toBe(3000);
+			expect(progress.calories.percentage).toBe(50);
+		});
+
+		it('should cap percentage at 100', () => {
+			const nutrition = { calories: 3000 };
+			const progress = calculateProgress(nutrition);
+
+			expect(progress.calories.percentage).toBe(100);
+		});
+
+		it('should handle missing values', () => {
+			const progress = calculateProgress({});
+
+			expect(progress.calories.current).toBe(0);
+			expect(progress.calories.percentage).toBe(0);
+		});
+	});
+
+	describe('sumNutrition', () => {
+		it('should sum multiple meals', () => {
+			const meals = [
+				{ nutrition: { calories: 500, protein: 20, carbohydrates: 60, fat: 15 } },
+				{ nutrition: { calories: 300, protein: 15, carbohydrates: 40, fat: 10 } },
+			];
+
+			const sum = sumNutrition(meals);
+
+			expect(sum.calories).toBe(800);
+			expect(sum.protein).toBe(35);
+			expect(sum.carbohydrates).toBe(100);
+			expect(sum.fat).toBe(25);
+		});
+
+		it('should handle null nutrition', () => {
+			const meals = [{ nutrition: { calories: 500 } }, { nutrition: null }];
+
+			const sum = sumNutrition(meals);
+
+			expect(sum.calories).toBe(500);
+		});
+
+		it('should handle empty array', () => {
+			const sum = sumNutrition([]);
+
+			expect(sum.calories).toBe(0);
+		});
+	});
+
+	describe('formatNutrient', () => {
+		it('should format calories', () => {
+			expect(formatNutrient('calories', 1234.5)).toBe('1235 kcal');
+		});
+
+		it('should format protein', () => {
+			expect(formatNutrient('protein', 25.5)).toBe('25.5 g');
+		});
+
+		it('should return dash for undefined', () => {
+			expect(formatNutrient('calories', undefined)).toBe('-');
+		});
+	});
+
+	describe('getProgressColor', () => {
+		it('should return red for low percentage', () => {
+			expect(getProgressColor(30)).toBe('#EF4444');
+		});
+
+		it('should return orange for medium percentage', () => {
+			expect(getProgressColor(60)).toBe('#F59E0B');
+		});
+
+		it('should return green for high percentage', () => {
+			expect(getProgressColor(90)).toBe('#22C55E');
+		});
+
+		it('should return red for over 100%', () => {
+			expect(getProgressColor(120)).toBe('#EF4444');
+		});
+	});
+
+	describe('detectDeficiencies', () => {
+		it('should detect low protein', () => {
+			const nutrition = { protein: 10 }; // 20% of 50g target
+			const deficiencies = detectDeficiencies(nutrition);
+
+			expect(deficiencies).toContainEqual(expect.objectContaining({ nutrient: 'protein' }));
+		});
+
+		it('should not detect deficiency when above threshold', () => {
+			const nutrition = { protein: 30 }; // 60% of target
+			const deficiencies = detectDeficiencies(nutrition);
+
+			expect(deficiencies.find((d) => d.nutrient === 'protein')).toBeUndefined();
+		});
+	});
+
+	describe('suggestMealType', () => {
+		beforeEach(() => {
+			vi.useFakeTimers();
+		});
+
+		afterEach(() => {
+			vi.useRealTimers();
+		});
+
+		it('should suggest breakfast in the morning', () => {
+			vi.setSystemTime(new Date('2024-01-15T08:00:00'));
+			expect(suggestMealType()).toBe('breakfast');
+		});
+
+		it('should suggest lunch at noon', () => {
+			vi.setSystemTime(new Date('2024-01-15T12:00:00'));
+			expect(suggestMealType()).toBe('lunch');
+		});
+
+		it('should suggest dinner in the evening', () => {
+			vi.setSystemTime(new Date('2024-01-15T19:00:00'));
+			expect(suggestMealType()).toBe('dinner');
+		});
+
+		it('should suggest snack at other times', () => {
+			vi.setSystemTime(new Date('2024-01-15T15:00:00'));
+			expect(suggestMealType()).toBe('snack');
+		});
+	});
+
+	describe('formatDateForDisplay', () => {
+		it('should format date in German', () => {
+			const date = new Date('2024-01-15');
+			const formatted = formatDateForDisplay(date, 'de-DE');
+
+			expect(formatted).toContain('15');
+			expect(formatted).toContain('Januar');
+		});
+	});
+
+	describe('isToday', () => {
+		it('should return true for today', () => {
+			expect(isToday(new Date())).toBe(true);
+		});
+
+		it('should return false for yesterday', () => {
+			const yesterday = new Date();
+			yesterday.setDate(yesterday.getDate() - 1);
+			expect(isToday(yesterday)).toBe(false);
+		});
+
+		it('should return false for same day different year', () => {
+			const lastYear = new Date();
+			lastYear.setFullYear(lastYear.getFullYear() - 1);
+			expect(isToday(lastYear)).toBe(false);
+		});
+	});
+});