Add new reusable components to shared-landing-ui package:
- AppScrollerSection, TimelineSection, MasonryGridSection, PrinciplesSection
- LegalPageTemplate for privacy/terms/cookies/imprint pages
- Navigation component with mobile menu and language switcher
- GradientText and LanguageSwitcher atoms
- i18n system with getLangFromUrl, useTranslations, localizePath
- Theme files for picture (indigo), chat (blue), zitare (teal)
Add legal pages to ManaDeck and Chat landing pages:
- privacy, terms, cookies, imprint pages using shared template
- Updated footers with cookies link
