[evm, simplex]: PERMIT2 mode for SimplexPaymaster

docs/content/developers/evm/intent-gateway/simplex.mdx

@@ -349,7 +349,7 @@ Create an API keypair in the Turnkey Dashboard under user details. The <code>sig
 
 Solver selection requires each solver's EOA to be delegated to the `SolverAccount` contract. Simplex performs this automatically at startup via EIP-7702:
 
-- **Primary path** — builds a no-op UserOperation with an attached EIP-7702 authorization and submits it through the configured bundler. When a paymaster is deployed on the chain — Circle Paymaster (USDC) preferred, then the `SimplexPaymaster` (USDC or USDT) — and the solver holds at least one whole token of a supported stablecoin, the paymaster pays gas in that stablecoin (via EIP-2612 permit, or a small capped approval for tokens without permit support such as BSC stables) so the solver never needs native gas for delegation.
+- **Primary path** — builds a no-op UserOperation with an attached EIP-7702 authorization and submits it through the configured bundler. When a paymaster is deployed on the chain — Circle Paymaster (USDC) preferred, then the `SimplexPaymaster` (USDC or USDT) — and the solver holds at least one whole token of a supported stablecoin, the paymaster pays gas in that stablecoin so the solver never needs native gas for delegation. Tokens with EIP-2612 are authorized by permit; tokens without it (such as BSC stables) need a one-time funded `approve(Permit2, max)` from the solver EOA, after which every operation carries a per-op Permit2 signature and no native gas is needed again.
 - **Fallback** — if the bundler path fails or the chain has no paymaster, Simplex sends a direct type-0x04 delegation tx using the solver's native balance. On paymaster-less chains it also keeps the ERC-4337 EntryPoint deposit topped up to cover `targetGasUnits` (default 3,000,000) at the current gas price.
 
 No manual steps are required — delegation is idempotent and skipped if the EOA is already delegated to the correct contract.

evm/script/SimplexPaymasterPermit2Probe.s.sol

@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.24;
+
+import "forge-std/Script.sol";
+import {ERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import {ERC1967Proxy} from "@openzeppelin/contracts/proxy/ERC1967/ERC1967Proxy.sol";
+import {ERC4337Utils} from "@openzeppelin/contracts/account/utils/draft-ERC4337Utils.sol";
+
+import {SimplexPaymaster, AggregatorV3Interface} from "../src/utils/SimplexPaymaster.sol";
+import {SolverAccount} from "../src/apps/intentsv2/SolverAccount.sol";
+
+/// @dev Freely mintable stand-in for a stablecoin without EIP-2612.
+contract ProbeToken is ERC20 {
+    constructor() ERC20("Probe USD", "pUSD") {}
+
+    function decimals() public pure override returns (uint8) {
+        return 6;
+    }
+
+    function mint(address to, uint256 amount) external {
+        _mint(to, amount);
+    }
+}
+
+/// @notice Base Sepolia side deployment for probing PERMIT2 mode through live bundlers:
+///         a mintable no-permit token priced off the USDC/USD feed, a SolverAccount to
+///         delegate to, and a fully configured, deposited and staked SimplexPaymaster.
+///         Usage: PRIVATE_KEY=... forge script script/SimplexPaymasterPermit2Probe.s.sol \
+///                --rpc-url <base-sepolia> --broadcast
+contract SimplexPaymasterPermit2ProbeScript is Script {
+    address constant HOST = 0x9AA003594d59C62EE17A73A569Fd7B1DbdBd71E1;
+    address constant INTENT_GATEWAY_V2 = 0x6CF42FA9BecbC5b6a26884964956b113530f7cFA;
+    address constant ETH_USD = 0x4aDC67696bA383F43DD60A9e78F2C97Fbbfc7cb1;
+    address constant USDC_USD = 0xd30e2101a97dcbAeBCBC04F14C3f624E67A35165;
+
+    function run() external {
+        uint256 pk = vm.envUint("PRIVATE_KEY");
+        address deployer = vm.addr(pk);
+        vm.startBroadcast(pk);
+
+        ProbeToken token = new ProbeToken();
+        token.mint(deployer, 1_000e6);
+
+        SolverAccount solverAccount = new SolverAccount(INTENT_GATEWAY_V2);
+
+        address[] memory tokens = new address[](1);
+        tokens[0] = address(token);
+        AggregatorV3Interface[] memory oracles = new AggregatorV3Interface[](1);
+        oracles[0] = AggregatorV3Interface(USDC_USD);
+
+        SimplexPaymaster implementation = new SimplexPaymaster();
+        bytes memory initData = abi.encodeCall(
+            SimplexPaymaster.initialize,
+            (
+                HOST,
+                SimplexPaymaster.Params({
+                    nativeOracle: AggregatorV3Interface(ETH_USD),
+                    markupBps: 200,
+                    treasury: deployer,
+                    maxOracleAge: 90_000,
+                    swapSlippageBps: 200
+                }),
+                tokens,
+                oracles
+            )
+        );
+        SimplexPaymaster paymaster = SimplexPaymaster(payable(address(new ERC1967Proxy(address(implementation), initData))));
+
+        ERC4337Utils.ENTRYPOINT_V08.depositTo{value: 0.05 ether}(address(paymaster));
+        paymaster.addStake{value: 0.1 ether}(86_400);
+
+        vm.stopBroadcast();
+
+        console.log("token:", address(token));
+        console.log("solverAccount:", address(solverAccount));
+        console.log("paymaster implementation:", address(implementation));
+        console.log("paymaster proxy:", address(paymaster));
+    }
+}