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/proxy/beacon/BeaconProxy.sol

@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v5.2.0) (proxy/beacon/BeaconProxy.sol)
+
+pragma solidity ^0.8.22;
+
+import {IBeacon} from "./IBeacon.sol";
+import {Proxy} from "../Proxy.sol";
+import {ERC1967Utils} from "../ERC1967/ERC1967Utils.sol";
+
+/**
+ * @dev This contract implements a proxy that gets the implementation address for each call from an {UpgradeableBeacon}.
+ *
+ * The beacon address can only be set once during construction, and cannot be changed afterwards. It is stored in an
+ * immutable variable to avoid unnecessary storage reads, and also in the beacon storage slot specified by
+ * https://eips.ethereum.org/EIPS/eip-1967[ERC-1967] so that it can be accessed externally.
+ *
+ * CAUTION: Since the beacon address can never be changed, you must ensure that you either control the beacon, or trust
+ * the beacon to not upgrade the implementation maliciously.
+ *
+ * IMPORTANT: Do not use the implementation logic to modify the beacon storage slot. Doing so would leave the proxy in
+ * an inconsistent state where the beacon storage slot does not match the beacon address.
+ */
+contract BeaconProxy is Proxy {
+    // An immutable address for the beacon to avoid unnecessary SLOADs before each delegate call.
+    address private immutable _beacon;
+
+    /**
+     * @dev Initializes the proxy with `beacon`.
+     *
+     * If `data` is nonempty, it's used as data in a delegate call to the implementation returned by the beacon. This
+     * will typically be an encoded function call, and allows initializing the storage of the proxy like a Solidity
+     * constructor.
+     *
+     * Requirements:
+     *
+     * - `beacon` must be a contract with the interface {IBeacon}.
+     * - If `data` is empty, `msg.value` must be zero.
+     */
+    constructor(address beacon, bytes memory data) payable {
+        ERC1967Utils.upgradeBeaconToAndCall(beacon, data);
+        _beacon = beacon;
+    }
+
+    /**
+     * @dev Returns the current implementation address of the associated beacon.
+     */
+    function _implementation() internal view virtual override returns (address) {
+        return IBeacon(_getBeacon()).implementation();
+    }
+
+    /**
+     * @dev Returns the beacon.
+     */
+    function _getBeacon() internal view virtual returns (address) {
+        return _beacon;
+    }
+}