- Update all date/time formatting functions to use 'es-ES' locale instead of 'en-US' or 'de-DE'
- Update utility functions in utils/date.ts and utils/exchange.ts
- Update all component files that use date formatting
- Update e2e test helper to match new Spanish date format
- All formatting now uses Spanish locale regardless of selected language as per PR requirements
- Created frontend/e2e/helpers/auth.ts with shared auth utilities
- Extracted getRequiredEnv, REGULAR_USER, ADMIN_USER, clearAuth, loginUser
- Updated all three e2e test files to use shared helpers
- Reduced code duplication across test files