Implement the POST /api/tutor/good-move endpoint

[programarivm]

src/Controller/TutorGoodMoveController.php is to be implemented to explain the why of a good move in terms of chess concepts.

Method	Endpoint	Description
POST	/api/tutor/good-move	Explains the why of a good move

Parameter	Type	Description	Required
fen	string	A FEN string.	Yes

Response	Description
200 (OK)	Returns a good move along with a chess position explanation
400 (Bad Request)	The request could not be processed

See:

• https://github.com/chesslablab/website/issues/235
• Explain a Good PGN Move

Keep it up, and happy coding!