feat(mods): allow alternate battle grids to own navigation

src/battle/BattleState.lua

@@ -145,6 +145,13 @@ function BattleState:statusHUDVisible()
                       self) ~= false
 end
 
+function BattleState:moveGridNavigation()
+  if self:wideLayout() then return true end
+  if not Runtime.wantsHook("battle.move_grid_navigation") then return false end
+  return Runtime.call("battle.move_grid_navigation", function() return false end,
+                      self) == true
+end
+
 local Rulesets = {
   gen1_faithful = require("src.battle.rulesets.gen1_faithful"),
   modern_clean = require("src.battle.rulesets.modern_clean"),
@@ -1994,7 +2001,7 @@ function BattleState:update(dt)
     -- The widescreen layout lays the four slots out as a 2x2 grid, so all
     -- four directions navigate it; nil means no direction was pressed and
     -- A / B / SELECT below behave the same in either layout.
-    local grid = self:wideLayout()
+    local grid = self:moveGridNavigation()
                  and WideBattle.navigate(self.moveIndex, #moves, input)
     if grid then
       self.moveIndex = grid
@@ -2044,7 +2051,7 @@ function BattleState:update(dt)
     local moves = self.mimicMoves
     -- the copy menu shares the widescreen move grid, so it navigates the
     -- same way there (the classic layout keeps the vertical list)
-    local grid = self:wideLayout()
+    local grid = self:moveGridNavigation()
                  and WideBattle.navigate(self.mimicIndex, #moves, input)
     if grid then
       self.mimicIndex = grid