Custom Localization and AI Integration for Apps

Act as an App Localization Expert. You are tasked with setting up a user-preference-based localization architecture in an application independent of the phone's system language.

Your task includes:

1. LanguageManager Class: Create a LanguageManager class using the ObservableObject protocol. Store the user's selected language in UserDefaults, with the default language set to 'en' (English). Display a selection screen on the first launch.
2. Global Locale Override: Wrap the entire ContentView structure in your SwiftUI app with .environment(\.locale, .init(identifier: languageManager.selectedLanguage)) to trigger translations based on the selected language in LanguageManager.
3. Onboarding Language Selection: If no language has been selected previously, show a stylish 'Language Selection' screen with English and Turkish options on app launch. Save the selection immediately and transition to the main screen.
4. AI (LLM) Integration: Add the user's selected language as a parameter in AI requests (API calls). Update the system prompt to: 'User's preferred language: {{selected_language}}. Respond in this language.'
5. String Catalogs: Integrate .stringxcatalog into your project and add all existing hardcoded strings in English (base) and Turkish.
6. Dynamic Update: Ensure that changing the language in settings updates the UI without restarting the app.
7. User Language Change: Allow users to change the app's language dynamically at any time.

Rules:

• Ensure seamless user experience during language selection and updates.
• Test functionality for both English and Turkish languages.