test: run fork test against mainnet deployment

tests/fork/Fork.t.sol

@@ -3,6 +3,7 @@ pragma solidity >=0.8.22;
 
 import { IERC20Metadata } from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
 import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import { SablierFlow } from "src/SablierFlow.sol";
 
 import { Base_Test } from "../Base.t.sol";
 
@@ -37,11 +38,16 @@ abstract contract Fork_Test is Base_Test {
     //////////////////////////////////////////////////////////////////////////*/
 
     function setUp() public virtual override {
-        // Fork Ethereum Mainnet at a specific block number. The block number is for the `OCT_1_2024` date.
-        vm.createSelectFork({ blockNumber: 20_866_919, urlOrAlias: "mainnet" });
+        // Fork Ethereum Mainnet at a block number during the Sablier deployment.
+        vm.createSelectFork({ blockNumber: 21_330_577, urlOrAlias: "mainnet" });
 
-        // The base is set up after the fork is selected so that the base test contracts are deployed on the fork.
-        Base_Test.setUp();
+        // Load mainnet address of flow.
+        flow = SablierFlow(0x2D9221a63E12AA796619cb381Ec4A71b201281f5);
+
+        // Label the flow contract.
+        vm.label(address(flow), "Flow");
+
+        resetPrank(users.sender);
 
         // Label the tokens.
         for (uint256 i = 0; i < tokens.length; ++i) {