Add comprehensive game flow documentation with ASCII diagrams

- Create GAME_FLOW_DIAGRAM.md with detailed visual representations of:
  * Complete match lifecycle state machine (scheduled → bet → ingame → completed)
  * Component interaction diagrams showing system architecture
  * Betting system flow from customer request to receipt generation
  * Timer and automation sequences with priority logic
  * Extraction process flow with redistribution cap logic
  * Error handling and recovery scenarios
  * Performance and scalability visualizations
- Include timing sequences, global betting mode comparisons, and bottleneck analysis