fix(contracts-rfq): configurable deployBlock

packages/contracts-rfq/contracts/AdminV2.sol

@@ -60,20 +60,32 @@ contract AdminV2 is AccessControlEnumerable, IAdminV2, IAdminV2Errors {
     /// @notice The delay period after which a transaction can be permissionlessly cancelled.
     uint256 public cancelDelay;
 
+    /// @notice The block number at which the contract was deployed.
+    /// @dev This used to be immutable in V1, but was adjusted to be mutable in V2 for chains like Arbitrum that
+    /// implement the `block.number` as the underlying L1 block number rather than the chain's native block number.
+    /// This is exposed for conveniece for off-chain indexers that need to know the deployment block.
+    uint256 public deployBlock;
+
     /// @notice This variable is deprecated and should not be used.
     /// @dev Use ZapNative V2 requests instead.
     uint256 public immutable chainGasAmount = 0;
 
     constructor(address defaultAdmin) {
         _grantRole(DEFAULT_ADMIN_ROLE, defaultAdmin);
         _setCancelDelay(DEFAULT_CANCEL_DELAY);
+        _setDeployBlock(block.number);
     }
 
     /// @inheritdoc IAdminV2
     function setCancelDelay(uint256 newCancelDelay) external onlyRole(GOVERNOR_ROLE) {
         _setCancelDelay(newCancelDelay);
     }
 
+    /// @inheritdoc IAdminV2
+    function setDeployBlock(uint256 blockNumber) external onlyRole(DEFAULT_ADMIN_ROLE) {
+        _setDeployBlock(blockNumber);
+    }
+
     /// @inheritdoc IAdminV2
     function setProtocolFeeRate(uint256 newFeeRate) external onlyRole(GOVERNOR_ROLE) {
         if (newFeeRate > FEE_RATE_MAX) revert FeeRateAboveMax();
@@ -106,4 +118,11 @@ contract AdminV2 is AccessControlEnumerable, IAdminV2, IAdminV2Errors {
         cancelDelay = newCancelDelay;
         emit CancelDelayUpdated(oldCancelDelay, newCancelDelay);
     }
+
+    /// @notice Internal logic to set the deploy block. Security checks are performed outside of this function.
+    /// @dev This function is marked as private to prevent child contracts from calling it directly.
+    function _setDeployBlock(uint256 blockNumber) private {
+        deployBlock = blockNumber;
+        emit DeployBlockSet(blockNumber);
+    }
 }

packages/contracts-rfq/contracts/FastBridgeV2.sol

@@ -52,14 +52,10 @@ contract FastBridgeV2 is AdminV2, MulticallTarget, IFastBridgeV2, IFastBridgeV2E
     /// @notice This variable is deprecated and should not be used.
     /// @dev Replaced by senderNonces.
     uint256 public immutable nonce = 0;
-    /// @notice The block number at which this contract was deployed.
-    uint256 public immutable deployBlock;
 
     /// @notice Initializes the FastBridgeV2 contract with the provided default admin,
     /// sets the default cancel delay, and records the deploy block number.
-    constructor(address defaultAdmin) AdminV2(defaultAdmin) {
-        deployBlock = block.number;
-    }
+    constructor(address defaultAdmin) AdminV2(defaultAdmin) {}
 
     // ══════════════════════════════════════ EXTERNAL MUTABLE (USER FACING) ═══════════════════════════════════════════
 

packages/contracts-rfq/contracts/interfaces/IAdminV2.sol

@@ -3,13 +3,19 @@ pragma solidity ^0.8.4;
 
 interface IAdminV2 {
     event CancelDelayUpdated(uint256 oldCancelDelay, uint256 newCancelDelay);
+    event DeployBlockSet(uint256 blockNumber);
     event FeeRateUpdated(uint256 oldFeeRate, uint256 newFeeRate);
     event FeesSwept(address token, address recipient, uint256 amount);
 
     /// @notice Allows the governor to set the cancel delay. The cancel delay is the time period after the transaction
     /// deadline during which a transaction can be permissionlessly cancelled if it hasn't been proven by any Relayer.
     function setCancelDelay(uint256 newCancelDelay) external;
 
+    /// @notice Allows the default admin to set the deploy block.
+    /// @dev This is only relevant for chains like Arbitrum that implement the `block.number` as the underlying L1
+    /// block number rather than the chain's native block number.
+    function setDeployBlock(uint256 blockNumber) external;
+
     /// @notice Allows the governor to set the protocol fee rate. The protocol fee is taken from the origin
     /// amount and is only applied to completed and claimed transactions.
     /// @dev The protocol fee is abstracted away from the relayers; they always operate using the amounts after fees.

packages/contracts-rfq/test/FastBridgeV2.Management.t.sol

@@ -18,6 +18,7 @@ contract FastBridgeV2ManagementTest is FastBridgeV2Test, IAdminV2Errors {
     address public governorA = makeAddr("Governor A");
 
     event CancelDelayUpdated(uint256 oldCancelDelay, uint256 newCancelDelay);
+    event DeployBlockSet(uint256 blockNumber);
     event FeeRateUpdated(uint256 oldFeeRate, uint256 newFeeRate);
     event FeesSwept(address token, address recipient, uint256 amount);
 
@@ -46,6 +47,11 @@ contract FastBridgeV2ManagementTest is FastBridgeV2Test, IAdminV2Errors {
         fastBridge.setCancelDelay(newCancelDelay);
     }
 
+    function setDeployBlock(address caller, uint256 blockNumber) public {
+        vm.prank(caller);
+        fastBridge.setDeployBlock(blockNumber);
+    }
+
     function setProtocolFeeRate(address caller, uint256 newFeeRate) public {
         vm.prank(caller);
         fastBridge.setProtocolFeeRate(newFeeRate);
@@ -68,8 +74,10 @@ contract FastBridgeV2ManagementTest is FastBridgeV2Test, IAdminV2Errors {
         setGovernor(caller, governorA);
     }
 
-    function test_defaultCancelDelay() public view {
+    function test_defaultValues() public view {
         assertEq(fastBridge.cancelDelay(), DEFAULT_CANCEL_DELAY);
+        assertEq(fastBridge.deployBlock(), block.number);
+        assertEq(fastBridge.protocolFeeRate(), 0);
     }
 
     // ═════════════════════════════════════════════ SET CANCEL DELAY ══════════════════════════════════════════════════
@@ -100,6 +108,21 @@ contract FastBridgeV2ManagementTest is FastBridgeV2Test, IAdminV2Errors {
         setCancelDelay(caller, 4 days);
     }
 
+    // ═════════════════════════════════════════════ SET DEPLOY BLOCK ══════════════════════════════════════════════════
+
+    function test_setDeployBlock() public {
+        vm.expectEmit(address(fastBridge));
+        emit DeployBlockSet(123_456);
+        setDeployBlock(admin, 123_456);
+        assertEq(fastBridge.deployBlock(), 123_456);
+    }
+
+    function test_setDeployBlock_revertNotAdmin(address caller) public {
+        vm.assume(caller != admin);
+        expectUnauthorized(caller, fastBridge.DEFAULT_ADMIN_ROLE());
+        setDeployBlock(caller, 123_456);
+    }
+
     // ═══════════════════════════════════════════ SET PROTOCOL FEE RATE ═══════════════════════════════════════════════
 
     function test_setProtocolFeeRate() public {