fix(test): one contract per file

rainix-sol-single-contract: test/abstract/BuildScript.t.sol declared both the
spy and the test contract. The spy moves to its own file.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: thedavidmeister

test/abstract/BuildScript.t.sol

@@ -3,29 +3,7 @@
 pragma solidity =0.8.25;
 
 import {Test} from "forge-std-1.16.1/src/Test.sol";
-import {BuildScript} from "src/abstract/BuildScript.sol";
-
-/// @notice Counts the hooks instead of running them, so the entrypoints are
-/// asserted on dispatch alone. The real `freeze` writes the tag dir named by
-/// `[package].version` — shared state that `LibSnapshot.t.sol` also drives, and
-/// forge runs test contracts concurrently, so touching it here would race
-/// rather than test.
-contract SpyBuildScript is BuildScript {
-    uint256 public builds;
-    uint256 public freezes;
-
-    function build() internal override {
-        builds++;
-    }
-
-    function snapshotContractNames() internal pure override returns (string[] memory names) {
-        names = new string[](0);
-    }
-
-    function freeze() internal override {
-        freezes++;
-    }
-}
+import {SpyBuildScript} from "./SpyBuildScript.sol";
 
 /// @title BuildScriptTest
 contract BuildScriptTest is Test {

test/abstract/SpyBuildScript.sol

@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: LicenseRef-DCL-1.0
+// SPDX-FileCopyrightText: Copyright (c) 2020 Rain Open Source Software Ltd
+pragma solidity =0.8.25;
+
+import {BuildScript} from "src/abstract/BuildScript.sol";
+
+/// @notice Counts the hooks instead of running them, so the entrypoints are
+/// asserted on dispatch alone. The real `freeze` writes the tag dir named by
+/// `[package].version` — shared state that `LibSnapshot.t.sol` also drives, and
+/// forge runs test contracts concurrently, so touching it here would race
+/// rather than test.
+contract SpyBuildScript is BuildScript {
+    uint256 public builds;
+    uint256 public freezes;
+
+    function build() internal override {
+        builds++;
+    }
+
+    function snapshotContractNames() internal pure override returns (string[] memory names) {
+        names = new string[](0);
+    }
+
+    function freeze() internal override {
+        freezes++;
+    }
+}