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/EscrowService.t.sol

@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.20;
+
+import "forge-std/Test.sol";
+import "../../contracts/EscrowService.sol";
+
+contract EscrowServiceFuzzTest is Test {
+    EscrowService public escrow;
+    address public owner;
+    address public provider;
+    address payable public client;
+
+    function setUp() public {
+        owner = address(this);
+        provider = makeAddr("provider");
+        client = payable(makeAddr("client"));
+        escrow = new EscrowService();
+    }
+
+    function invariant_balanceInvariant() public {
+        assertEq(address(escrow).balance, 0, "Escrow should hold no stray ETH after operations");
+    }
+
+    function testFuzz_EscrowFlow(uint256 amount) public {
+        vm.assume(amount >= 0.01 ether && amount <= 100 ether);
+        vm.deal(client, amount + 1 ether);
+
+        vm.prank(client);
+        escrow.deposit{value: amount}(provider);
+        assertEq(escrow.getBalance(provider), amount);
+
+        vm.prank(owner);
+        escrow.release(provider, client);
+        assertEq(escrow.getBalance(provider), 0);
+    }
+}