✨ 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/package.json

@@ -11,10 +11,13 @@
 		"./constants": "./src/constants/index.ts"
 	},
 	"scripts": {
-		"type-check": "tsc --noEmit"
+		"type-check": "tsc --noEmit",
+		"test": "vitest run",
+		"test:watch": "vitest"
 	},
 	"devDependencies": {
-		"typescript": "~5.9.2"
+		"typescript": "~5.9.2",
+		"vitest": "^2.1.8"
 	},
 	"dependencies": {}
 }