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/hardhat/templates/hardhat-2/03-mocha-ethers-ts/contracts/Lock.sol

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.28;
+
+// Uncomment this line to use console.log
+// import "hardhat/console.sol";
+
+contract Lock {
+  uint public unlockTime;
+  address payable public owner;
+
+  event Withdrawal(uint amount, uint when);
+
+  constructor(uint _unlockTime) payable {
+    require(
+      block.timestamp < _unlockTime,
+      "Unlock time should be in the future"
+    );
+
+    unlockTime = _unlockTime;
+    owner = payable(msg.sender);
+  }
+
+  function withdraw() public {
+    // Uncomment this line, and the import of "hardhat/console.sol", to print a log in your terminal
+    // console.log("Unlock time is %o and block timestamp is %o", unlockTime, block.timestamp);
+
+    require(block.timestamp >= unlockTime, "You can't withdraw yet");
+    require(msg.sender == owner, "You aren't the owner");
+
+    emit Withdrawal(address(this).balance, block.timestamp);
+
+    owner.transfer(address(this).balance);
+  }
+}