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/utils/Panic.sol

@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v5.1.0) (utils/Panic.sol)
+
+pragma solidity ^0.8.20;
+
+/**
+ * @dev Helper library for emitting standardized panic codes.
+ *
+ * ```solidity
+ * contract Example {
+ *      using Panic for uint256;
+ *
+ *      // Use any of the declared internal constants
+ *      function foo() { Panic.GENERIC.panic(); }
+ *
+ *      // Alternatively
+ *      function foo() { Panic.panic(Panic.GENERIC); }
+ * }
+ * ```
+ *
+ * Follows the list from https://github.com/ethereum/solidity/blob/v0.8.24/libsolutil/ErrorCodes.h[libsolutil].
+ *
+ * _Available since v5.1._
+ */
+// slither-disable-next-line unused-state
+library Panic {
+    /// @dev generic / unspecified error
+    uint256 internal constant GENERIC = 0x00;
+    /// @dev used by the assert() builtin
+    uint256 internal constant ASSERT = 0x01;
+    /// @dev arithmetic underflow or overflow
+    uint256 internal constant UNDER_OVERFLOW = 0x11;
+    /// @dev division or modulo by zero
+    uint256 internal constant DIVISION_BY_ZERO = 0x12;
+    /// @dev enum conversion error
+    uint256 internal constant ENUM_CONVERSION_ERROR = 0x21;
+    /// @dev invalid encoding in storage
+    uint256 internal constant STORAGE_ENCODING_ERROR = 0x22;
+    /// @dev empty array pop
+    uint256 internal constant EMPTY_ARRAY_POP = 0x31;
+    /// @dev array out of bounds access
+    uint256 internal constant ARRAY_OUT_OF_BOUNDS = 0x32;
+    /// @dev resource error (too large allocation or too large array)
+    uint256 internal constant RESOURCE_ERROR = 0x41;
+    /// @dev calling invalid internal function
+    uint256 internal constant INVALID_INTERNAL_FUNCTION = 0x51;
+
+    /// @dev Reverts with a panic code. Recommended to use with
+    /// the internal constants with predefined codes.
+    function panic(uint256 code) internal pure {
+        assembly ("memory-safe") {
+            mstore(0x00, 0x4e487b71)
+            mstore(0x20, code)
+            revert(0x1c, 0x24)
+        }
+    }
+}