[PR #38] p3: constructor zero-address guards (!aavePool, !swapRouter) have no tests

[obchain]

Summary

CharonLiquidator's constructor validates both constructor arguments:

require(_aavePool != address(0), "!aavePool");
require(_swapRouter != address(0), "!swapRouter");

Neither guard is tested. These are the only immutable configuration checks for the contract's two critical external dependencies. If either address is misconfigured at deploy time, the contract is permanently bricked (immutables cannot be changed post-deploy).

Location

contracts/test/CharonLiquidator.t.sol — no constructor tests present

Fix

Add two tests (can be in a new Section F — Constructor):

function test_constructor_revertsOnZeroAavePool() public {
    vm.expectRevert(bytes("!aavePool"));
    new CharonLiquidator(address(0), STUB_ROUTER);
}

function test_constructor_revertsOnZeroSwapRouter() public {
    vm.expectRevert(bytes("!swapRouter"));
    new CharonLiquidator(STUB_POOL, address(0));
}

Refs #38

[obchain]

Fixed via commit 6447016. Two new tests:

• test_constructor_revertsOnZeroAavePool deploys CharonLiquidator with _aavePool = address(0) and asserts revert !aavePool.
• test_constructor_revertsOnZeroSwapRouter deploys with _swapRouter = address(0) and asserts revert !swapRouter.
  The corresponding cold-wallet zero-address test will land post-rebase along with the feat/12 COLD_WALLET constructor arg (see deferred [PR #38] p2: CLAUDE.md safety invariant (profit to cold wallet) has no test coverage #129).