docs(Lock): enhance contract documentation

contracts/Lock.sol

@@ -1,15 +1,40 @@
 // SPDX-License-Identifier: UNLICENSED
+
+/**
+ * @title Lock
+ * @dev A simple time-locked contract that allows the owner to withdraw funds after a specified unlock time.
+ * The contract is initialized with an unlock time and can receive ETH. Only the owner can withdraw after the unlock time.
+ */
 pragma solidity ^0.8.28;
 
 // Uncomment this line to use console.log
 // import "hardhat/console.sol";
 
 contract Lock {
+    /**
+     * @dev The timestamp when funds can be withdrawn.
+     */
     uint public unlockTime;
+
+    /**
+     * @dev The address of the contract owner who can withdraw funds.
+     */
     address payable public owner;
 
+    /**
+     * @dev Emitted when a withdrawal is made.
+     * @param amount The amount withdrawn (entire contract balance).
+     * @param when The timestamp when the withdrawal occurred.
+     */
     event Withdrawal(uint amount, uint when);
 
+    /**
+     * @dev Initializes the contract with a future unlock time. Sets the deployer as the owner.
+     * @param _unlockTime The timestamp after which funds can be withdrawn.
+     * Requirements:
+     * - _unlockTime must be in the future.
+     * - Contract can receive ETH at deployment.
+     */
     constructor(uint _unlockTime) payable {
         require(
             block.timestamp < _unlockTime,
@@ -20,6 +45,13 @@ contract Lock {
         owner = payable(msg.sender);
     }
 
+    /**
+     * @dev Allows the owner to withdraw all funds after the unlock time.
+     * Requirements:
+     * - Current time must be greater than or equal to unlockTime.
+     * - Caller must be the owner.
+     * Emits a {Withdrawal} event.
+     */
     function withdraw() public {
         // Uncomment this line, and the import of "hardhat/console.sol", to print a log in your terminal
         // console.log("Unlock time is %o and block timestamp is %o", unlockTime, block.timestamp);