Add MultiInit contract and update error name

src/initializers/MultiInit.sol

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.20;
+
+import {LibDiamond} from "@diamond/libraries/LibDiamond.sol";
+import {AddressAndCalldataLengthMismatch} from "@diamond/libraries/errors/DiamondErrors.sol";
+
+contract MultiInit {
+    function multiInit(address[] memory _initAddresses, bytes[] memory _initData) public {
+        uint256 initAddressesLength = _initAddresses.length;
+        if (initAddressesLength != _initData.length) revert AddressAndCalldataLengthMismatch();
+
+        for (uint256 i; i < initAddressesLength; ++i) {
+            LibDiamond._initializeDiamondCut(_initAddresses[i], _initData[i]);
+        }
+    }
+}

src/libraries/errors/DiamondErrors.sol

@@ -74,4 +74,4 @@ error FunctionDoesNotExist(bytes4 functionSelector);
 
 /// @notice Thrown when the length of the address array does not match the length of the calldata array.
 /// @dev Used in initializer logic to ensure one-to-one mapping between addresses and initialization calldata.
-error AddressAndCalldataLengthDoNotMatch();
+error AddressAndCalldataLengthMismatch();