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/finance/VestingWallet.sol

@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v5.3.0) (finance/VestingWallet.sol)
+pragma solidity ^0.8.20;
+
+import {IERC20} from "../token/ERC20/IERC20.sol";
+import {SafeERC20} from "../token/ERC20/utils/SafeERC20.sol";
+import {Address} from "../utils/Address.sol";
+import {Context} from "../utils/Context.sol";
+import {Ownable} from "../access/Ownable.sol";
+
+/**
+ * @dev A vesting wallet is an ownable contract that can receive native currency and ERC-20 tokens, and release these
+ * assets to the wallet owner, also referred to as "beneficiary", according to a vesting schedule.
+ *
+ * Any assets transferred to this contract will follow the vesting schedule as if they were locked from the beginning.
+ * Consequently, if the vesting has already started, any amount of tokens sent to this contract will (at least partly)
+ * be immediately releasable.
+ *
+ * By setting the duration to 0, one can configure this contract to behave like an asset timelock that holds tokens for
+ * a beneficiary until a specified time.
+ *
+ * NOTE: Since the wallet is {Ownable}, and ownership can be transferred, it is possible to sell unvested tokens.
+ * Preventing this in a smart contract is difficult, considering that: 1) a beneficiary address could be a
+ * counterfactually deployed contract, 2) there is likely to be a migration path for EOAs to become contracts in the
+ * near future.
+ *
+ * NOTE: When using this contract with any token whose balance is adjusted automatically (i.e. a rebase token), make
+ * sure to account the supply/balance adjustment in the vesting schedule to ensure the vested amount is as intended.
+ *
+ * NOTE: Chains with support for native ERC20s may allow the vesting wallet to withdraw the underlying asset as both an
+ * ERC20 and as native currency. For example, if chain C supports token A and the wallet gets deposited 100 A, then
+ * at 50% of the vesting period, the beneficiary can withdraw 50 A as ERC20 and 25 A as native currency (totaling 75 A).
+ * Consider disabling one of the withdrawal methods.
+ */
+contract VestingWallet is Context, Ownable {
+    event EtherReleased(uint256 amount);
+    event ERC20Released(address indexed token, uint256 amount);
+
+    uint256 private _released;
+    mapping(address token => uint256) private _erc20Released;
+    uint64 private immutable _start;
+    uint64 private immutable _duration;
+
+    /**
+     * @dev Sets the beneficiary (owner), the start timestamp and the vesting duration (in seconds) of the vesting
+     * wallet.
+     */
+    constructor(address beneficiary, uint64 startTimestamp, uint64 durationSeconds) payable Ownable(beneficiary) {
+        _start = startTimestamp;
+        _duration = durationSeconds;
+    }
+
+    /**
+     * @dev The contract should be able to receive Eth.
+     */
+    receive() external payable virtual {}
+
+    /**
+     * @dev Getter for the start timestamp.
+     */
+    function start() public view virtual returns (uint256) {
+        return _start;
+    }
+
+    /**
+     * @dev Getter for the vesting duration.
+     */
+    function duration() public view virtual returns (uint256) {
+        return _duration;
+    }
+
+    /**
+     * @dev Getter for the end timestamp.
+     */
+    function end() public view virtual returns (uint256) {
+        return start() + duration();
+    }
+
+    /**
+     * @dev Amount of eth already released
+     */
+    function released() public view virtual returns (uint256) {
+        return _released;
+    }
+
+    /**
+     * @dev Amount of token already released
+     */
+    function released(address token) public view virtual returns (uint256) {
+        return _erc20Released[token];
+    }
+
+    /**
+     * @dev Getter for the amount of releasable eth.
+     */
+    function releasable() public view virtual returns (uint256) {
+        return vestedAmount(uint64(block.timestamp)) - released();
+    }
+
+    /**
+     * @dev Getter for the amount of releasable `token` tokens. `token` should be the address of an
+     * {IERC20} contract.
+     */
+    function releasable(address token) public view virtual returns (uint256) {
+        return vestedAmount(token, uint64(block.timestamp)) - released(token);
+    }
+
+    /**
+     * @dev Release the native token (ether) that have already vested.
+     *
+     * Emits a {EtherReleased} event.
+     */
+    function release() public virtual {
+        uint256 amount = releasable();
+        _released += amount;
+        emit EtherReleased(amount);
+        Address.sendValue(payable(owner()), amount);
+    }
+
+    /**
+     * @dev Release the tokens that have already vested.
+     *
+     * Emits a {ERC20Released} event.
+     */
+    function release(address token) public virtual {
+        uint256 amount = releasable(token);
+        _erc20Released[token] += amount;
+        emit ERC20Released(token, amount);
+        SafeERC20.safeTransfer(IERC20(token), owner(), amount);
+    }
+
+    /**
+     * @dev Calculates the amount of ether that has already vested. Default implementation is a linear vesting curve.
+     */
+    function vestedAmount(uint64 timestamp) public view virtual returns (uint256) {
+        return _vestingSchedule(address(this).balance + released(), timestamp);
+    }
+
+    /**
+     * @dev Calculates the amount of tokens that has already vested. Default implementation is a linear vesting curve.
+     */
+    function vestedAmount(address token, uint64 timestamp) public view virtual returns (uint256) {
+        return _vestingSchedule(IERC20(token).balanceOf(address(this)) + released(token), timestamp);
+    }
+
+    /**
+     * @dev Virtual implementation of the vesting formula. This returns the amount vested, as a function of time, for
+     * an asset given its total historical allocation.
+     */
+    function _vestingSchedule(uint256 totalAllocation, uint64 timestamp) internal view virtual returns (uint256) {
+        if (timestamp < start()) {
+            return 0;
+        } else if (timestamp >= end()) {
+            return totalAllocation;
+        } else {
+            return (totalAllocation * (timestamp - start())) / duration();
+        }
+    }
+}

dev/env/node_modules/@openzeppelin/contracts/finance/VestingWalletCliff.sol

@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v5.1.0) (finance/VestingWalletCliff.sol)
+
+pragma solidity ^0.8.20;
+
+import {SafeCast} from "../utils/math/SafeCast.sol";
+import {VestingWallet} from "./VestingWallet.sol";
+
+/**
+ * @dev Extension of {VestingWallet} that adds a cliff to the vesting schedule.
+ *
+ * _Available since v5.1._
+ */
+abstract contract VestingWalletCliff is VestingWallet {
+    using SafeCast for *;
+
+    uint64 private immutable _cliff;
+
+    /// @dev The specified cliff duration is larger than the vesting duration.
+    error InvalidCliffDuration(uint64 cliffSeconds, uint64 durationSeconds);
+
+    /**
+     * @dev Set the duration of the cliff, in seconds. The cliff starts vesting schedule (see {VestingWallet}'s
+     * constructor) and ends `cliffSeconds` later.
+     */
+    constructor(uint64 cliffSeconds) {
+        if (cliffSeconds > duration()) {
+            revert InvalidCliffDuration(cliffSeconds, duration().toUint64());
+        }
+        _cliff = start().toUint64() + cliffSeconds;
+    }
+
+    /**
+     * @dev Getter for the cliff timestamp.
+     */
+    function cliff() public view virtual returns (uint256) {
+        return _cliff;
+    }
+
+    /**
+     * @dev Virtual implementation of the vesting formula. This returns the amount vested, as a function of time, for
+     * an asset given its total historical allocation. Returns 0 if the {cliff} timestamp is not met.
+     *
+     * IMPORTANT: The cliff not only makes the schedule return 0, but it also ignores every possible side
+     * effect from calling the inherited implementation (i.e. `super._vestingSchedule`). Carefully consider
+     * this caveat if the overridden implementation of this function has any (e.g. writing to memory or reverting).
+     */
+    function _vestingSchedule(
+        uint256 totalAllocation,
+        uint64 timestamp
+    ) internal view virtual override returns (uint256) {
+        return timestamp < cliff() ? 0 : super._vestingSchedule(totalAllocation, timestamp);
+    }
+}