Add complete Texas Hold'em poker gameplay including:
- Pure function game engine (deck, dealing, betting, showdown)
- Hand evaluator supporting all 10 poker hand ranks
- Animated card components with 3D flip transitions
- CSS Grid oval poker table layout for up to 9 seats
- Player seat components with chip tracking and turn indicators
- Bet controls with conditional button visibility
- Basic AI opponents with random valid action selection
- Turn advancement, all-in auto-advance, and dealer rotation
Sync delta specs to main specs: poker-table, card-components,
game-engine, player-state.
