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/ethers/src.ts/crypto/hmac.ts

@@ -0,0 +1,51 @@
+/**
+ *  An **HMAC** enables verification that a given key was used
+ *  to authenticate a payload.
+ *
+ *  See: [[link-wiki-hmac]]
+ *
+ *  @_subsection: api/crypto:HMAC  [about-hmac]
+ */
+import { createHmac } from "./crypto.js";
+import { getBytes, hexlify } from "../utils/index.js";
+
+import type { BytesLike } from "../utils/index.js";
+
+
+let locked = false;
+
+const _computeHmac = function(algorithm: "sha256" | "sha512", key: Uint8Array, data: Uint8Array): BytesLike {
+    return createHmac(algorithm, key).update(data).digest();
+}
+
+let __computeHmac = _computeHmac;
+
+/**
+ *  Return the HMAC for %%data%% using the %%key%% key with the underlying
+ *  %%algo%% used for compression.
+ *
+ *  @example:
+ *    key = id("some-secret")
+ *
+ *    // Compute the HMAC
+ *    computeHmac("sha256", key, "0x1337")
+ *    //_result:
+ *
+ *    // To compute the HMAC of UTF-8 data, the data must be
+ *    // converted to UTF-8 bytes
+ *    computeHmac("sha256", key, toUtf8Bytes("Hello World"))
+ *    //_result:
+ *
+ */
+export function computeHmac(algorithm: "sha256" | "sha512", _key: BytesLike, _data: BytesLike): string {
+    const key = getBytes(_key, "key");
+    const data = getBytes(_data, "data");
+    return hexlify(__computeHmac(algorithm, key, data));
+}
+computeHmac._ = _computeHmac;
+computeHmac.lock =  function() { locked = true; }
+computeHmac.register = function(func: (algorithm: "sha256" | "sha512", key: Uint8Array, data: Uint8Array) => BytesLike) {
+    if (locked) { throw new Error("computeHmac is locked"); }
+    __computeHmac = func;
+}
+Object.freeze(computeHmac);