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/cryptography/verifiers/ERC7913P256Verifier.sol

@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v5.4.0) (utils/cryptography/verifiers/ERC7913P256Verifier.sol)
+
+pragma solidity ^0.8.20;
+
+import {P256} from "../../../utils/cryptography/P256.sol";
+import {IERC7913SignatureVerifier} from "../../../interfaces/IERC7913.sol";
+
+/**
+ * @dev ERC-7913 signature verifier that support P256 (secp256r1) keys.
+ *
+ * @custom:stateless
+ */
+contract ERC7913P256Verifier is IERC7913SignatureVerifier {
+    /// @inheritdoc IERC7913SignatureVerifier
+    function verify(bytes calldata key, bytes32 hash, bytes calldata signature) public view virtual returns (bytes4) {
+        // Signature length may be 0x40 or 0x41.
+        if (key.length == 0x40 && signature.length >= 0x40) {
+            bytes32 qx = bytes32(key[0x00:0x20]);
+            bytes32 qy = bytes32(key[0x20:0x40]);
+            bytes32 r = bytes32(signature[0x00:0x20]);
+            bytes32 s = bytes32(signature[0x20:0x40]);
+            if (P256.verify(hash, r, s, qx, qy)) {
+                return IERC7913SignatureVerifier.verify.selector;
+            }
+        }
+        return 0xFFFFFFFF;
+    }
+}

dev/env/node_modules/@openzeppelin/contracts/utils/cryptography/verifiers/ERC7913RSAVerifier.sol

@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts (last updated v5.4.0) (utils/cryptography/verifiers/ERC7913RSAVerifier.sol)
+
+pragma solidity ^0.8.20;
+
+import {RSA} from "../../../utils/cryptography/RSA.sol";
+import {IERC7913SignatureVerifier} from "../../../interfaces/IERC7913.sol";
+
+/**
+ * @dev ERC-7913 signature verifier that support RSA keys.
+ *
+ * @custom:stateless
+ */
+contract ERC7913RSAVerifier is IERC7913SignatureVerifier {
+    /// @inheritdoc IERC7913SignatureVerifier
+    function verify(bytes calldata key, bytes32 hash, bytes calldata signature) public view virtual returns (bytes4) {
+        (bytes memory e, bytes memory n) = abi.decode(key, (bytes, bytes));
+        return
+            RSA.pkcs1Sha256(abi.encodePacked(hash), signature, e, n)
+                ? IERC7913SignatureVerifier.verify.selector
+                : bytes4(0xFFFFFFFF);
+    }
+}