chore(security): enhance environment configuration, CI workflows, and wallet daemon with security improvements

- Restructure .env.example with security-focused documentation, service-specific environment file references, and AWS Secrets Manager integration
- Update CLI tests workflow to single Python 3.13 version, add pytest-mock dependency, and consolidate test execution with coverage
- Add comprehensive security validation to package publishing workflow with manual approval gates, secret scanning, and release

contracts/test/fuzz/AIPowerRental.t.sol

@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.20;
+
+import "forge-std/Test.sol";
+import "../../contracts/AIPowerRental.sol";
+
+contract AIPowerRentalFuzzTest is Test {
+    AIPowerRental public rental;
+    address public owner;
+    address public provider;
+    address payable public renter;
+
+    function setUp() public {
+        owner = address(this);
+        provider = makeAddr("provider");
+        renter = payable(makeAddr("renter"));
+        rental = new AIPowerRental();
+    }
+
+    function invariant_balanceInvariant() public {
+        assertEq(address(rental).balance, 0, "Contract should hold no stray ETH");
+    }
+
+    function testFuzz_RentalFlow(uint256 duration, uint256 price) public {
+        vm.assume(duration > 0 && duration <= 365 days);
+        vm.assume(price >= 0.001 ether && price <= 10 ether);
+        
+        uint256 rentAmount = price * duration / 1 days;
+        vm.deal(renter, rentAmount + 1 ether);
+        
+        vm.prank(provider);
+        rental.createRental(price, duration);
+        
+        uint256 rentalId = 0;
+        vm.prank(renter);
+        rental.startRental{value: rentAmount}(rentalId);
+        
+        assertEq(rental.getRentalEnd(rentalId), block.timestamp + duration);
+    }
+}