L0: Verify audit suite builds + runs locally, fix setup friction

.gitignore

@@ -3,3 +3,4 @@ cache/
 lib/
 node_modules/
 .env
+**/__pycache__/

README.md

@@ -28,6 +28,28 @@ forge install kcolbchain/audit-checklist
 When working on this repository directly, initialize submodules before running
 the local verification commands:
 
+### Prerequisites
+
+- **Foundry** (forge + cast): Install via [foundryup](https://book.getfoundry.sh/getting-started/installation).
+  - ⚠️ **Linux users**: The latest forge binaries require **GLIBC >= 2.33**.
+    Run `ldd --version` to check. If you're on an older distro (e.g. CentOS 8,
+    Ubuntu 20.04 with stock glibc), use the [Foundry Docker image](https://ghcr.io/foundry-rs/foundry):
+    ```bash
+    docker pull ghcr.io/foundry-rs/foundry:latest
+    docker run --rm -v "$PWD":/workspace -w /workspace ghcr.io/foundry-rs/foundry:latest forge test
+    ```
+- **Slither** (optional, for static analysis): `pip install slither-analyzer`
+  - Memory-constrained hosts can run specific detectors:
+    ```bash
+    slither . --config slither.config.json --detect reentrancy-eth,uninitialized-state,unchecked-transfer
+    ```
+  - Full analysis (may need 4 GB+ RAM):
+    ```bash
+    slither . --config slither.config.json
+    ```
+
+### Quick verification
+
 ```bash
 git submodule update --init --recursive
 forge build

src/checks/ERC777ReentrancyCheck.sol

@@ -29,6 +29,8 @@ abstract contract ERC777ReentrancyCheck is ChecklistBase {
 
     /// @dev Perform a deposit as `depositor` of `amount`. Override to match
     ///      your target's deposit flow (approve+pull, push, etc.).
+    /// @notice Implementations MUST use `vm.prank(depositor)` (or `vm.startPrank`/`vm.stopPrank`)
+    ///         before the deposit call so that the target contract sees `depositor` as `msg.sender`.
     function performDeposit(address depositor, uint256 amount) internal virtual;
 
     function test_erc777_reentrancy_on_withdraw() public {

src/checks/ReentrancyCheck.sol

@@ -16,7 +16,11 @@ abstract contract ReentrancyCheck is ChecklistBase {
         return 1 ether;
     }
 
-    /// @dev Override to perform a deposit into the target contract
+    /// @dev Override to perform a deposit into the target contract as `depositor`.
+    /// @notice Implementations MUST use `vm.prank(depositor)` (or `vm.startPrank`/`vm.stopPrank`)
+    ///         before the deposit call so that the target contract sees `depositor` as `msg.sender`.
+    ///         The check function does NOT call `vm.prank` before this hook to avoid prank-stacking
+    ///         errors in Foundry >= 1.0.
     function performDeposit(address depositor, uint256 amount) internal virtual;
 
     function test_reentrancy_on_withdraw() public {
@@ -27,15 +31,17 @@ abstract contract ReentrancyCheck is ChecklistBase {
         uint256 depositAmount = getDepositValue();
         vm.deal(attacker, depositAmount);
 
-        // Deposit as the attacker
-        vm.prank(attacker);
+        // Deposit as the attacker.
+        // NOTE: performDeposit handles msg.sender internally via vm.prank.
+        // Do NOT add vm.prank(attacker) here — it would stack with the prank
+        // inside performDeposit and cause Foundry >= 1.0 to throw
+        // "cannot overwrite a prank until it is applied at least once".
         performDeposit(attacker, depositAmount);
 
         uint256 targetBalBefore = address(targetContract).balance;
 
         // Trigger the attack — attacker calls withdraw, which sends ETH,
         // which triggers receive(), which re-enters withdraw()
-        vm.prank(attacker);
         ReentrantAttacker(payable(attacker)).attack();
 
         uint256 attackerBal = address(attacker).balance;