doc: document lobby conversation structure very important

horse/game-id.kk

@@ -17,7 +17,7 @@ pub struct character-id
 
 // Game ID for trainees, i.e. costume instances of characters.
 // Generally a character ID with two digits appended.
-pub struct trainee-id
+pub struct uma-id
   game-id: game-id
 
 // Game ID for skills.

horse/trainee.kk

@@ -1,18 +0,0 @@
-module horse/trainee
-
-import horse/game-id
-import horse/movement
-import horse/race
-
-// Details of a trainee.
-pub struct trainee-detail
-  turf: level
-  dirt: level
-  sprint: level
-  mile: level
-  medium: level
-  long: level
-  front-runner: level
-  pace-chaser: level
-  late-surger: level
-  end-closer: level