Byte: Add adjacency check to validator

Author: Perlkonig

locales/en/apgames.json

@@ -3296,6 +3296,7 @@
             "NORMALISE": "The move needs to be normalised. Try '{{normalised}}'."
         },
         "byte": {
+            "ADJ_ONLY": "Stacks may only move to adjacent cells.",
             "DIAG_ONLY": "Stacks may only move diagonally.",
             "INITIAL_INSTRUCTIONS": "Select a stack to move. If merging stacks, select the bottom checker you wish to move.",
             "INVALID_INDEX": "There is no checker at position {{index}} in the stack at {{where}}.",

src/games/byte.ts

@@ -377,6 +377,12 @@ export class ByteGame extends GameBase {
                 result.message = i18next.t("apgames:validation._general.SAME_FROM_TO");
                 return result;
             }
+            // must be adjacent
+            if (!graph.neighbours(from).includes(to)) {
+                result.valid = false;
+                result.message = i18next.t("apgames:validation.byte.ADJ_ONLY");
+                return result;
+            }
             // can only move diagonally
             const [tox, toy] = graph.algebraic2coords(to);
             if (tox % 2 === toy % 2) {