fix(game3/battle): guard from_rom and move_target_byte against nil ROM pack in headless tests

src/core/game3/battle/ai.lua

@@ -124,8 +124,8 @@ end
 local function move_target_byte(mv)
   if move_num(mv) == 0 then return 0 end
   local Moves = require("src.core.game3.battle.moves")
-  local m = Moves.get(mv)
-  return tonumber(m and m.target) or 0
+  local ok, m = pcall(Moves.get, mv)
+  return tonumber(ok and m and m.target) or 0
 end
 
 local function random_u16(rng)

src/core/game3/battle/moves.lua

@@ -116,6 +116,7 @@ end
 
 local function from_rom(numId)
   Moves.romReady()
+  if not Moves._rom then return nil end
   local row = Moves._rom[numId]
   if not row then return nil end
   local cat = Types.isPhysical(row.type) and "physical" or "special"