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/Proxy.sol

@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v5.0.0) (proxy/Proxy.sol)
+
+pragma solidity ^0.8.20;
+
+/**
+ * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
+ * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
+ * be specified by overriding the virtual {_implementation} function.
+ *
+ * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
+ * different contract through the {_delegate} function.
+ *
+ * The success and return data of the delegated call will be returned back to the caller of the proxy.
+ */
+abstract contract Proxy {
+    /**
+     * @dev Delegates the current call to `implementation`.
+     *
+     * This function does not return to its internal call site, it will return directly to the external caller.
+     */
+    function _delegate(address implementation) internal virtual {
+        assembly {
+            // Copy msg.data. We take full control of memory in this inline assembly
+            // block because it will not return to Solidity code. We overwrite the
+            // Solidity scratch pad at memory position 0.
+            calldatacopy(0, 0, calldatasize())
+
+            // Call the implementation.
+            // out and outsize are 0 because we don't know the size yet.
+            let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)
+
+            // Copy the returned data.
+            returndatacopy(0, 0, returndatasize())
+
+            switch result
+            // delegatecall returns 0 on error.
+            case 0 {
+                revert(0, returndatasize())
+            }
+            default {
+                return(0, returndatasize())
+            }
+        }
+    }
+
+    /**
+     * @dev This is a virtual function that should be overridden so it returns the address to which the fallback
+     * function and {_fallback} should delegate.
+     */
+    function _implementation() internal view virtual returns (address);
+
+    /**
+     * @dev Delegates the current call to the address returned by `_implementation()`.
+     *
+     * This function does not return to its internal call site, it will return directly to the external caller.
+     */
+    function _fallback() internal virtual {
+        _delegate(_implementation());
+    }
+
+    /**
+     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
+     * function in the contract matches the call data.
+     */
+    fallback() external payable virtual {
+        _fallback();
+    }
+}