no setsid on macos

CLAUDE.md

@@ -19,7 +19,7 @@ Transcript-based shell integration test runner. Bun + TypeScript.
 ## Architecture
 
 - `src/parse.ts` — parses `.shout` files into `ShoutFile` (list of `Command`)
-- `src/run.ts` — executes commands via `Bun.spawn(["setsid", "/bin/sh"])`, captures output with sentinels
+- `src/run.ts` — executes commands via `Bun.spawn(["/bin/sh"], { detached: true })`, captures output with sentinels
 - `src/match.ts` — wildcard-aware output matching and diff generation
 - `src/format.ts` — evaluates pass/fail, formats failures and summary
 - `src/update.ts` — rewrites `.shout` files with actual output (`--update` mode)

src/run.ts

@@ -137,7 +137,8 @@ export async function runFile(
     env["PATH"] = options.pathDirs.join(":") + ":" + (env["PATH"] ?? "")
   }
 
-  const proc = Bun.spawn(["setsid", "/bin/sh"], {
+  const proc = Bun.spawn(["/bin/sh"], {
+    detached: true,
     stdin: "pipe",
     stdout: "pipe",
     stderr: "pipe",