only store one snake with the same type and move Calculations into moves as the array<json> type

dbschema/default.esdl

@@ -34,10 +34,8 @@ module default {
       readonly := true;
       on source delete delete target;
     }
-    single snake: Snake {
+    required single snake: Snake {
       readonly := true;
-      on source delete delete target;
-      on target delete allow;
     }
   }
 
@@ -68,7 +66,7 @@ module default {
     required type: str {
       readonly := true;
     }
-    #constraint exclusive on .type;
+    constraint exclusive on ( .type );
   }
 
   type Moves {
@@ -81,15 +79,7 @@ module default {
     required game_board: json {
       readonly := true;
     }
-    single calculations: Calculations {
-      readonly := true;
-      on source delete delete target;
-      on target delete allow;
-    }
-  }
-
-  type Calculations {
-    required data: array<json> {
+    calculations: array<json> {
       readonly := true;
     }
   }

server/storage/EdgeDB.py

@@ -47,11 +47,7 @@ class EdgeDB:
               turn := data.turn,
               snake_move := data.`move`,
               game_board := data.game_board,
-              calculations := (
-                insert Calculations {
-                  data := data.calculations
-                }
-              )
+              calculations := data.calculations
             }
         ),
         type := (
@@ -70,7 +66,7 @@ class EdgeDB:
         snake := (
           insert Snake {
             type := <str>$snake_type
-          }
+          } unless conflict on .type else Snake
         )
       }""",