[UI/UX] ARENA Tab - Games Hub Improvements

[ucguy4u]

Part of #187

Tab Purpose

Gaming and entertainment

Required Changes

• Welcome text and game categories
• Game cards with entire card tappable
• Category sections: Card Games, Strategy, Coming Soon
• Game rules accessible from each card

UX Rules

• No music player visible
• No greetings, no quotes

Files

• app/lib/features/games/presentation/screens/games_hub_screen.dart
• app/lib/features/games/presentation/widgets/game_card.dart