evm: Add CCTP request

.cspell/custom-dictionary.txt

@@ -1,5 +1,6 @@
 # Custom Dictionary Words
 Aptos
+CCTP
 Devnet
 hashv
 idls

evm/src/libraries/ExecutorMessages.sol

@@ -5,6 +5,7 @@ library ExecutorMessages {
     bytes4 private constant REQ_MM = "ERM1";
     bytes4 private constant REQ_VAA_V1 = "ERV1";
     bytes4 private constant REQ_NTT_V1 = "ERN1";
+    bytes4 private constant REQ_CCTP_V1 = "ERC1";
 
     /// @notice Payload length will not fit in a uint32.
     /// @dev Selector: 492f620d.
@@ -54,4 +55,12 @@ library ExecutorMessages {
     {
         return abi.encodePacked(REQ_NTT_V1, srcChain, srcManager, messageId);
     }
+
+    /// @notice Encodes a version 1 CCTP request payload.
+    /// @param sourceDomain The source chain for the CCTP transfer.
+    /// @param nonce The nonce of the CCTP transfer.
+    /// @return bytes The encoded request.
+    function makeCCTPv1Request(uint32 sourceDomain, uint64 nonce) internal pure returns (bytes memory) {
+        return abi.encodePacked(REQ_CCTP_V1, sourceDomain, nonce);
+    }
 }

evm/test/ExecutorMessages.t.sol

@@ -38,4 +38,12 @@ contract ExecutorMessagesTest is Test {
         bytes memory buf = ExecutorMessages.makeNTTv1Request(srcChain, srcManager, messageId);
         assertEq(keccak256(expected), keccak256(buf));
     }
+
+    function test_makeCCTPv1Request() public pure {
+        uint32 srcDomain = 7;
+        uint64 nonce = 42;
+        bytes memory expected = abi.encodePacked("ERC1", srcDomain, nonce);
+        bytes memory buf = ExecutorMessages.makeCCTPv1Request(srcDomain, nonce);
+        assertEq(keccak256(expected), keccak256(buf));
+    }
 }