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/hardhat/templates/hardhat-2/01-mocha-ethers-js/test/Lock.js

@@ -0,0 +1,126 @@
+const {
+  time,
+  loadFixture,
+} = require("@nomicfoundation/hardhat-toolbox/network-helpers");
+const { anyValue } = require("@nomicfoundation/hardhat-chai-matchers/withArgs");
+const { expect } = require("chai");
+
+describe("Lock", function () {
+  // We define a fixture to reuse the same setup in every test.
+  // We use loadFixture to run this setup once, snapshot that state,
+  // and reset Hardhat Network to that snapshot in every test.
+  async function deployOneYearLockFixture() {
+    const ONE_YEAR_IN_SECS = 365 * 24 * 60 * 60;
+    const ONE_GWEI = 1_000_000_000;
+
+    const lockedAmount = ONE_GWEI;
+    const unlockTime = (await time.latest()) + ONE_YEAR_IN_SECS;
+
+    // Contracts are deployed using the first signer/account by default
+    const [owner, otherAccount] = await ethers.getSigners();
+
+    const Lock = await ethers.getContractFactory("Lock");
+    const lock = await Lock.deploy(unlockTime, { value: lockedAmount });
+
+    return { lock, unlockTime, lockedAmount, owner, otherAccount };
+  }
+
+  describe("Deployment", function () {
+    it("Should set the right unlockTime", async function () {
+      const { lock, unlockTime } = await loadFixture(deployOneYearLockFixture);
+
+      expect(await lock.unlockTime()).to.equal(unlockTime);
+    });
+
+    it("Should set the right owner", async function () {
+      const { lock, owner } = await loadFixture(deployOneYearLockFixture);
+
+      expect(await lock.owner()).to.equal(owner.address);
+    });
+
+    it("Should receive and store the funds to lock", async function () {
+      const { lock, lockedAmount } = await loadFixture(
+        deployOneYearLockFixture,
+      );
+
+      expect(await ethers.provider.getBalance(lock.target)).to.equal(
+        lockedAmount,
+      );
+    });
+
+    it("Should fail if the unlockTime is not in the future", async function () {
+      // We don't use the fixture here because we want a different deployment
+      const latestTime = await time.latest();
+      const Lock = await ethers.getContractFactory("Lock");
+      await expect(Lock.deploy(latestTime, { value: 1 })).to.be.revertedWith(
+        "Unlock time should be in the future",
+      );
+    });
+  });
+
+  describe("Withdrawals", function () {
+    describe("Validations", function () {
+      it("Should revert with the right error if called too soon", async function () {
+        const { lock } = await loadFixture(deployOneYearLockFixture);
+
+        await expect(lock.withdraw()).to.be.revertedWith(
+          "You can't withdraw yet",
+        );
+      });
+
+      it("Should revert with the right error if called from another account", async function () {
+        const { lock, unlockTime, otherAccount } = await loadFixture(
+          deployOneYearLockFixture,
+        );
+
+        // We can increase the time in Hardhat Network
+        await time.increaseTo(unlockTime);
+
+        // We use lock.connect() to send a transaction from another account
+        await expect(lock.connect(otherAccount).withdraw()).to.be.revertedWith(
+          "You aren't the owner",
+        );
+      });
+
+      it("Shouldn't fail if the unlockTime has arrived and the owner calls it", async function () {
+        const { lock, unlockTime } = await loadFixture(
+          deployOneYearLockFixture,
+        );
+
+        // Transactions are sent using the first signer by default
+        await time.increaseTo(unlockTime);
+
+        await expect(lock.withdraw()).not.to.be.reverted;
+      });
+    });
+
+    describe("Events", function () {
+      it("Should emit an event on withdrawals", async function () {
+        const { lock, unlockTime, lockedAmount } = await loadFixture(
+          deployOneYearLockFixture,
+        );
+
+        await time.increaseTo(unlockTime);
+
+        await expect(lock.withdraw())
+          .to.emit(lock, "Withdrawal")
+          .withArgs(lockedAmount, anyValue); // We accept any value as `when` arg
+      });
+    });
+
+    describe("Transfers", function () {
+      it("Should transfer the funds to the owner", async function () {
+        const { lock, unlockTime, lockedAmount, owner } = await loadFixture(
+          deployOneYearLockFixture,
+        );
+
+        await time.increaseTo(unlockTime);
+
+        await expect(lock.withdraw()).to.changeEtherBalances(
+          [owner, lock],
+          [lockedAmount, -lockedAmount],
+        );
+      });
+    });
+  });
+});