refactor: move brother_node development artifact to dev/test-nodes subdirectory

Development Artifact Cleanup:
✅ BROTHER_NODE REORGANIZATION: Moved development test node to appropriate location
- dev/test-nodes/brother_node/: Moved from root directory for better organization
- Contains development configuration, test logs, and test chain data
- No impact on production systems - purely development/testing artifact

✅ DEVELOPMENT ARTIFACTS IDENTIFIED:
- Chain ID: aitbc-brother-chain (test/development chain)
- Ports: 8010 (P2P) and 8011 (RPC) - different from production
- Environment: .env file with test configuration
- Logs: rpc.log and node.log from development testing session (March 15, 2026)

✅ ROOT DIRECTORY CLEANUP: Removed development clutter from production directory
- brother_node/ moved to dev/test-nodes/brother_node/
- Root directory now contains only production-ready components
- Development artifacts properly organized in dev/ subdirectory

DIRECTORY STRUCTURE IMPROVEMENT:
📁 dev/test-nodes/: Development and testing node configurations
🏗️ Root Directory: Clean production structure with only essential components
🧪 Development Isolation: Test environments separated from production

BENEFITS:
✅ Clean Production Directory: No development artifacts in root
✅ Better Organization: Development nodes grouped in dev/ subdirectory
✅ Clear Separation: Production vs development environments clearly distinguished
✅ Maintainability: Easier to identify and manage development components

RESULT: Successfully moved brother_node development artifact to dev/test-nodes/ subdirectory, cleaning up the root directory while preserving development testing environment for future use.

dev/env/node_modules/@openzeppelin/contracts/token/ERC1155/utils/ERC1155Holder.sol

@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC1155/utils/ERC1155Holder.sol)
+
+pragma solidity ^0.8.20;
+
+import {IERC165, ERC165} from "../../../utils/introspection/ERC165.sol";
+import {IERC1155Receiver} from "../IERC1155Receiver.sol";
+
+/**
+ * @dev Simple implementation of `IERC1155Receiver` that will allow a contract to hold ERC-1155 tokens.
+ *
+ * IMPORTANT: When inheriting this contract, you must include a way to use the received tokens, otherwise they will be
+ * stuck.
+ */
+abstract contract ERC1155Holder is ERC165, IERC1155Receiver {
+    /// @inheritdoc IERC165
+    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
+        return interfaceId == type(IERC1155Receiver).interfaceId || super.supportsInterface(interfaceId);
+    }
+
+    function onERC1155Received(
+        address,
+        address,
+        uint256,
+        uint256,
+        bytes memory
+    ) public virtual override returns (bytes4) {
+        return this.onERC1155Received.selector;
+    }
+
+    function onERC1155BatchReceived(
+        address,
+        address,
+        uint256[] memory,
+        uint256[] memory,
+        bytes memory
+    ) public virtual override returns (bytes4) {
+        return this.onERC1155BatchReceived.selector;
+    }
+}

dev/env/node_modules/@openzeppelin/contracts/token/ERC1155/utils/ERC1155Utils.sol

@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC1155/utils/ERC1155Utils.sol)
+
+pragma solidity ^0.8.20;
+
+import {IERC1155Receiver} from "../IERC1155Receiver.sol";
+import {IERC1155Errors} from "../../../interfaces/draft-IERC6093.sol";
+
+/**
+ * @dev Library that provide common ERC-1155 utility functions.
+ *
+ * See https://eips.ethereum.org/EIPS/eip-1155[ERC-1155].
+ *
+ * _Available since v5.1._
+ */
+library ERC1155Utils {
+    /**
+     * @dev Performs an acceptance check for the provided `operator` by calling {IERC1155Receiver-onERC1155Received}
+     * on the `to` address. The `operator` is generally the address that initiated the token transfer (i.e. `msg.sender`).
+     *
+     * The acceptance call is not executed and treated as a no-op if the target address doesn't contain code (i.e. an EOA).
+     * Otherwise, the recipient must implement {IERC1155Receiver-onERC1155Received} and return the acceptance magic value to accept
+     * the transfer.
+     */
+    function checkOnERC1155Received(
+        address operator,
+        address from,
+        address to,
+        uint256 id,
+        uint256 value,
+        bytes memory data
+    ) internal {
+        if (to.code.length > 0) {
+            try IERC1155Receiver(to).onERC1155Received(operator, from, id, value, data) returns (bytes4 response) {
+                if (response != IERC1155Receiver.onERC1155Received.selector) {
+                    // Tokens rejected
+                    revert IERC1155Errors.ERC1155InvalidReceiver(to);
+                }
+            } catch (bytes memory reason) {
+                if (reason.length == 0) {
+                    // non-IERC1155Receiver implementer
+                    revert IERC1155Errors.ERC1155InvalidReceiver(to);
+                } else {
+                    assembly ("memory-safe") {
+                        revert(add(reason, 0x20), mload(reason))
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * @dev Performs a batch acceptance check for the provided `operator` by calling {IERC1155Receiver-onERC1155BatchReceived}
+     * on the `to` address. The `operator` is generally the address that initiated the token transfer (i.e. `msg.sender`).
+     *
+     * The acceptance call is not executed and treated as a no-op if the target address doesn't contain code (i.e. an EOA).
+     * Otherwise, the recipient must implement {IERC1155Receiver-onERC1155Received} and return the acceptance magic value to accept
+     * the transfer.
+     */
+    function checkOnERC1155BatchReceived(
+        address operator,
+        address from,
+        address to,
+        uint256[] memory ids,
+        uint256[] memory values,
+        bytes memory data
+    ) internal {
+        if (to.code.length > 0) {
+            try IERC1155Receiver(to).onERC1155BatchReceived(operator, from, ids, values, data) returns (
+                bytes4 response
+            ) {
+                if (response != IERC1155Receiver.onERC1155BatchReceived.selector) {
+                    // Tokens rejected
+                    revert IERC1155Errors.ERC1155InvalidReceiver(to);
+                }
+            } catch (bytes memory reason) {
+                if (reason.length == 0) {
+                    // non-IERC1155Receiver implementer
+                    revert IERC1155Errors.ERC1155InvalidReceiver(to);
+                } else {
+                    assembly ("memory-safe") {
+                        revert(add(reason, 0x20), mload(reason))
+                    }
+                }
+            }
+        }
+    }
+}