Add pre-level introduction screen to explain EDA game objects

Currently, players are directly taken into Level 1 without any prior explanation of the core Event Driven Architecture (EDA) concepts used in the game.

This can cause confusion for first-time players, as objects such as:

- Events
- Filters
- Sinks
- Transformers
- Dead Letter Queue (DLQ)

are introduced only during gameplay, without prior context.