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/utils/UUPSUpgradeable.sol

@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v5.3.0) (proxy/utils/UUPSUpgradeable.sol)
+
+pragma solidity ^0.8.22;
+
+import {IERC1822Proxiable} from "../../interfaces/draft-IERC1822.sol";
+import {ERC1967Utils} from "../ERC1967/ERC1967Utils.sol";
+
+/**
+ * @dev An upgradeability mechanism designed for UUPS proxies. The functions included here can perform an upgrade of an
+ * {ERC1967Proxy}, when this contract is set as the implementation behind such a proxy.
+ *
+ * A security mechanism ensures that an upgrade does not turn off upgradeability accidentally, although this risk is
+ * reinstated if the upgrade retains upgradeability but removes the security mechanism, e.g. by replacing
+ * `UUPSUpgradeable` with a custom implementation of upgrades.
+ *
+ * The {_authorizeUpgrade} function must be overridden to include access restriction to the upgrade mechanism.
+ */
+abstract contract UUPSUpgradeable is IERC1822Proxiable {
+    /// @custom:oz-upgrades-unsafe-allow state-variable-immutable
+    address private immutable __self = address(this);
+
+    /**
+     * @dev The version of the upgrade interface of the contract. If this getter is missing, both `upgradeTo(address)`
+     * and `upgradeToAndCall(address,bytes)` are present, and `upgradeTo` must be used if no function should be called,
+     * while `upgradeToAndCall` will invoke the `receive` function if the second argument is the empty byte string.
+     * If the getter returns `"5.0.0"`, only `upgradeToAndCall(address,bytes)` is present, and the second argument must
+     * be the empty byte string if no function should be called, making it impossible to invoke the `receive` function
+     * during an upgrade.
+     */
+    string public constant UPGRADE_INTERFACE_VERSION = "5.0.0";
+
+    /**
+     * @dev The call is from an unauthorized context.
+     */
+    error UUPSUnauthorizedCallContext();
+
+    /**
+     * @dev The storage `slot` is unsupported as a UUID.
+     */
+    error UUPSUnsupportedProxiableUUID(bytes32 slot);
+
+    /**
+     * @dev Check that the execution is being performed through a delegatecall call and that the execution context is
+     * a proxy contract with an implementation (as defined in ERC-1967) pointing to self. This should only be the case
+     * for UUPS and transparent proxies that are using the current contract as their implementation. Execution of a
+     * function through ERC-1167 minimal proxies (clones) would not normally pass this test, but is not guaranteed to
+     * fail.
+     */
+    modifier onlyProxy() {
+        _checkProxy();
+        _;
+    }
+
+    /**
+     * @dev Check that the execution is not being performed through a delegate call. This allows a function to be
+     * callable on the implementing contract but not through proxies.
+     */
+    modifier notDelegated() {
+        _checkNotDelegated();
+        _;
+    }
+
+    /**
+     * @dev Implementation of the ERC-1822 {proxiableUUID} function. This returns the storage slot used by the
+     * implementation. It is used to validate the implementation's compatibility when performing an upgrade.
+     *
+     * IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks
+     * bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this
+     * function revert if invoked through a proxy. This is guaranteed by the `notDelegated` modifier.
+     */
+    function proxiableUUID() external view virtual notDelegated returns (bytes32) {
+        return ERC1967Utils.IMPLEMENTATION_SLOT;
+    }
+
+    /**
+     * @dev Upgrade the implementation of the proxy to `newImplementation`, and subsequently execute the function call
+     * encoded in `data`.
+     *
+     * Calls {_authorizeUpgrade}.
+     *
+     * Emits an {Upgraded} event.
+     *
+     * @custom:oz-upgrades-unsafe-allow-reachable delegatecall
+     */
+    function upgradeToAndCall(address newImplementation, bytes memory data) public payable virtual onlyProxy {
+        _authorizeUpgrade(newImplementation);
+        _upgradeToAndCallUUPS(newImplementation, data);
+    }
+
+    /**
+     * @dev Reverts if the execution is not performed via delegatecall or the execution
+     * context is not of a proxy with an ERC-1967 compliant implementation pointing to self.
+     */
+    function _checkProxy() internal view virtual {
+        if (
+            address(this) == __self || // Must be called through delegatecall
+            ERC1967Utils.getImplementation() != __self // Must be called through an active proxy
+        ) {
+            revert UUPSUnauthorizedCallContext();
+        }
+    }
+
+    /**
+     * @dev Reverts if the execution is performed via delegatecall.
+     * See {notDelegated}.
+     */
+    function _checkNotDelegated() internal view virtual {
+        if (address(this) != __self) {
+            // Must not be called through delegatecall
+            revert UUPSUnauthorizedCallContext();
+        }
+    }
+
+    /**
+     * @dev Function that should revert when `msg.sender` is not authorized to upgrade the contract. Called by
+     * {upgradeToAndCall}.
+     *
+     * Normally, this function will use an xref:access.adoc[access control] modifier such as {Ownable-onlyOwner}.
+     *
+     * ```solidity
+     * function _authorizeUpgrade(address) internal onlyOwner {}
+     * ```
+     */
+    function _authorizeUpgrade(address newImplementation) internal virtual;
+
+    /**
+     * @dev Performs an implementation upgrade with a security check for UUPS proxies, and additional setup call.
+     *
+     * As a security check, {proxiableUUID} is invoked in the new implementation, and the return value
+     * is expected to be the implementation slot in ERC-1967.
+     *
+     * Emits an {IERC1967-Upgraded} event.
+     */
+    function _upgradeToAndCallUUPS(address newImplementation, bytes memory data) private {
+        try IERC1822Proxiable(newImplementation).proxiableUUID() returns (bytes32 slot) {
+            if (slot != ERC1967Utils.IMPLEMENTATION_SLOT) {
+                revert UUPSUnsupportedProxiableUUID(slot);
+            }
+            ERC1967Utils.upgradeToAndCall(newImplementation, data);
+        } catch {
+            // The implementation is not UUPS
+            revert ERC1967Utils.ERC1967InvalidImplementation(newImplementation);
+        }
+    }
+}