fix(run): preserve pnpm test selection arguments (#2092)

src/features/run/scriptArgs.ts

@@ -0,0 +1,7 @@
+import { commandName } from "./commandName";
+
+/** pnpm forwards `--` to the script, where it ends the test runner's option parsing. */
+export function appendScriptArgs(command: string, args: string[], extra: string[]): string[] {
+  const separator = !args.includes("--") && ["npm", "yarn", "bun"].includes(commandName(command)) ? ["--"] : [];
+  return [...args, ...separator, ...extra];
+}