Update the ECS engine to support automatic mutation tracking for
singletons during iteration, removing the need for manual
`MarkModified` calls.
- Update `ComponentDiscoveryGenerator` to detect singleton components.
- Refactor `PlaceMarkCommand` and `WinCheckSystem` to leverage
automatic mutation marking.
- Replace `ForEach` usage with `Select` and `ItemN` access in tests
and systems to align with the updated iterator API.
Enhance the OECS framework to support more robust component
deserialization during world serialization. This includes adding
boxed component support and a runtime fallback for component
discovery.
Additionally, introduces snapshot testing patterns for Blackjack
and TicTacToe to allow for manual verification of world state and
reactivity logs.
- Move examples (Blackjack, TicTacToe) to the root directory
- Convert example projects from Console applications to Libraries
- Add Directory.Build.props for shared build settings
- Update solution file and project references to reflect new paths