Cover required imports across platforms

tests/engine/ios_required_import_picker_test.lua

@@ -0,0 +1,32 @@
+-- iOS required imports travel through the same document-picker contract as
+-- Android. Keep the Swift bridge and liblove patch aligned: a build that has
+-- only one side would show the import button but fail on device.
+local function read(path)
+  local file = assert(io.open(path, "rb"))
+  local data = file:read("*a")
+  file:close()
+  return data
+end
+
+local function check(value, message)
+  if not value then error(message, 2) end
+end
+
+local bridge = read("mobile/ios/native/GRPickerBridge.swift")
+check(bridge:find('case "required_import":', 1, true)
+    and bridge:find('destName = "picked_required_import.bin"', 1, true),
+  "iOS routes required imports to their own staged filename")
+check(bridge:find("types.append(.data)", 1, true)
+    and bridge:find("types.append(.item)", 1, true),
+  "iOS required imports accept user-owned binary ROM files")
+check(bridge:find('"rom,mod,sav,stadium,required_import"', 1, true),
+  "iOS advertises required_import to Lua before opening the picker")
+
+local patch = read("mobile/ios/patch_love_src.py")
+check(patch:find("int w_pickFileKinds", 1, true)
+    and patch:find('{ "pickFileKinds", w_pickFileKinds }', 1, true),
+  "iOS liblove patch exposes the picker capability query")
+check(patch:find('("GRPickerBridge.swift", ID_FILE_PICKER', 1, true),
+  "iOS build patch compiles the required-import picker bridge")
+
+print("ios_required_import_picker_test: ok")