Store and retrieve persistent player data using EOS Player Data Storage

Steps

1. Obtain the Player Data Storage interface handle via EOS_Platform_GetPlayerDataStorageInterface after initializing the EOS platform.
2. To write a file, call EOS_PlayerDataStorage_WriteFile with a file name, the local data buffer, and transfer callbacks (EOS_PlayerDataStorage_OnWriteFileDataCallback) that supply data in chunks.
3. To read a file, call EOS_PlayerDataStorage_ReadFile with the file name and read callbacks (EOS_PlayerDataStorage_OnReadFileDataCallback) that receive data chunks and assemble the full payload.
4. Query available files for a player using EOS_PlayerDataStorage_QueryFileList and EOS_PlayerDataStorage_CopyFileMetadataAtIndex to enumerate file names and sizes before reading.
5. Delete files when no longer needed via EOS_PlayerDataStorage_DeleteFile to stay within storage quotas.
6. Handle EOS_NotFound result codes gracefully (e.g., first-time players will have no save files); initialize defaults in that case rather than treating it as a hard error.