Use a system-independent property to identify the graph storage path.
Update world engine for player coming to the game.

Update the graph, create feedback for players in the game.
Rename input for phraser as game events.
Extract inner WorldGraph as a package private independent class.
First turn-around-message trip. Failing to persist the graph.

Make the whole cycle for player connection to textual feedback.
Define the graph dir as a configuration property.
Define WorldGraph as singleton (possibly not needed [issue] below).
Make some refactoring.

[issue] looks like the graph doesn't see the prepopulated nodes on
successive calls.