feat: hardcode callback and swap selection in dispatcher

foundry/src/Dispatcher.sol

@@ -55,7 +55,6 @@ contract Dispatcher {
     // slither-disable-next-line delegatecall-loop
     function _callExecutor(
         address executor,
-        bytes4 selector,
         uint256 amount,
         bytes calldata data
     ) internal returns (uint256 calculatedAmount) {
@@ -63,10 +62,9 @@ contract Dispatcher {
             revert Dispatcher__UnapprovedExecutor();
         }
 
-        selector = selector == bytes4(0) ? IExecutor.swap.selector : selector;
         // slither-disable-next-line controlled-delegatecall,low-level-calls
         (bool success, bytes memory result) = executor.delegatecall(
-            abi.encodeWithSelector(selector, amount, data)
+            abi.encodeWithSelector(IExecutor.swap.selector, amount, data)
         );
 
         if (!success) {
@@ -83,18 +81,16 @@ contract Dispatcher {
     }
 
     function _handleCallback(bytes calldata data) internal {
-        bytes4 selector = bytes4(data[data.length - 4:]);
         address executor = address(uint160(bytes20(data[data.length - 24:])));
 
         if (!executors[executor]) {
             revert Dispatcher__UnapprovedExecutor();
         }
 
-        selector =
-            selector == bytes4(0) ? ICallback.handleCallback.selector : selector;
         // slither-disable-next-line controlled-delegatecall,low-level-calls
-        (bool success, bytes memory result) =
-            executor.delegatecall(abi.encodeWithSelector(selector, data));
+        (bool success, bytes memory result) = executor.delegatecall(
+            abi.encodeWithSelector(ICallback.handleCallback.selector, data)
+        );
 
         if (!success) {
             revert(

foundry/src/TychoRouter.sol

@@ -286,10 +286,7 @@ contract TychoRouter is AccessControl, Dispatcher, Pausable, ReentrancyGuard {
                 : remainingAmounts[tokenInIndex];
 
             currentAmountOut = _callExecutor(
-                swapData.executor(),
-                swapData.executorSelector(),
-                currentAmountIn,
-                swapData.protocolData()
+                swapData.executor(), currentAmountIn, swapData.protocolData()
             );
             amounts[tokenOutIndex] += currentAmountOut;
             remainingAmounts[tokenOutIndex] += currentAmountOut;

foundry/src/executors/UniswapV4Executor.sol

@@ -16,10 +16,11 @@ import {V4Router} from "@uniswap/v4-periphery/src/V4Router.sol";
 import {Actions} from "@uniswap/v4-periphery/src/libraries/Actions.sol";
 import {IV4Router} from "@uniswap/v4-periphery/src/interfaces/IV4Router.sol";
 import {PathKey} from "@uniswap/v4-periphery/src/libraries/PathKey.sol";
+import {ICallback} from "@interfaces/ICallback.sol";
 
 error UniswapV4Executor__InvalidDataLength();
 
-contract UniswapV4Executor is IExecutor, V4Router {
+contract UniswapV4Executor is IExecutor, V4Router, ICallback {
     using SafeERC20 for IERC20;
     using CurrencyLibrary for Currency;
 
@@ -176,6 +177,16 @@ contract UniswapV4Executor is IExecutor, V4Router {
         }
     }
 
+    function handleCallback(bytes calldata data)
+        external
+        returns (bytes memory)
+    {
+        verifyCallback(data);
+        return _unlockCallback(data);
+    }
+
+    function verifyCallback(bytes calldata) public view onlyPoolManager {}
+
     function _pay(Currency token, address, uint256 amount) internal override {
         IERC20(Currency.unwrap(token)).safeTransfer(
             address(poolManager), amount