refactor(test): reuse env snapshot helper

src/test-utils/env.ts

@@ -0,0 +1,18 @@
+export function captureEnv(keys: string[]) {
+  const snapshot = new Map<string, string | undefined>();
+  for (const key of keys) {
+    snapshot.set(key, process.env[key]);
+  }
+
+  return {
+    restore() {
+      for (const [key, value] of snapshot) {
+        if (value === undefined) {
+          delete process.env[key];
+        } else {
+          process.env[key] = value;
+        }
+      }
+    },
+  };
+}