Add new ErrorModal component for API error display:
- Auto-displays when apiError store is set
- Shows service name, error message, and status code
- Provides "Retry Connection" button to attempt reconnection
- Provides "Dismiss" button to close modal and continue
- Integrates with all three services (AniList, MAL, Simkl)
- Uses flowbite-svelte Modal and Button components
- Proper Svelte event handling with on:click
Uses Tailwind CSS for styling with red error theme and helpful messaging.
