feat: Add TokenTransfer class to Curve

- This needed to be in Curve so that the executor can also take care of transfers from the user into the tycho router, to avoid having transfer actions mixed between the router and executors

foundry/test/executors/CurveExecutor.t.sol

@@ -22,7 +22,9 @@ interface MetaRegistry {
 }
 
 contract CurveExecutorExposed is CurveExecutor {
-    constructor(address _nativeToken) CurveExecutor(_nativeToken) {}
+    constructor(address _nativeToken, address _permit2)
+        CurveExecutor(_nativeToken, _permit2)
+    {}
 
     function decodeData(bytes calldata data)
         external
@@ -34,7 +36,8 @@ contract CurveExecutorExposed is CurveExecutor {
             uint8 poolType,
             int128 i,
             int128 j,
-            bool tokenApprovalNeeded
+            bool tokenApprovalNeeded,
+            TokenTransfer.TransferType transferType
         )
     {
         return _decodeData(data);
@@ -50,7 +53,8 @@ contract CurveExecutorTest is Test, Constants {
     function setUp() public {
         uint256 forkBlock = 22031795;
         vm.createSelectFork(vm.rpcUrl("mainnet"), forkBlock);
-        curveExecutorExposed = new CurveExecutorExposed(ETH_ADDR_FOR_CURVE);
+        curveExecutorExposed =
+            new CurveExecutorExposed(ETH_ADDR_FOR_CURVE, PERMIT2_ADDRESS);
         metaRegistry = MetaRegistry(CURVE_META_REGISTRY);
     }
 
@@ -62,7 +66,8 @@ contract CurveExecutorTest is Test, Constants {
             uint8(3),
             uint8(2),
             uint8(0),
-            true
+            true,
+            TokenTransfer.TransferType.NONE
         );
 
         (
@@ -72,7 +77,8 @@ contract CurveExecutorTest is Test, Constants {
             uint8 poolType,
             int128 i,
             int128 j,
-            bool tokenApprovalNeeded
+            bool tokenApprovalNeeded,
+            TokenTransfer.TransferType transferType
         ) = curveExecutorExposed.decodeData(data);
 
         assertEq(tokenIn, WETH_ADDR);
@@ -82,6 +88,7 @@ contract CurveExecutorTest is Test, Constants {
         assertEq(i, 2);
         assertEq(j, 0);
         assertEq(tokenApprovalNeeded, true);
+        assertEq(uint8(transferType), uint8(TokenTransfer.TransferType.NONE));
     }
 
     function testTriPool() public {
@@ -311,7 +318,8 @@ contract CurveExecutorTest is Test, Constants {
             poolType,
             uint8(uint256(uint128(i))),
             uint8(uint256(uint128(j))),
-            true
+            true,
+            TokenTransfer.TransferType.NONE
         );
     }