fix(app): terminal pty isolation

packages/app/src/utils/terminal-writer.test.ts

@@ -0,0 +1,33 @@
+import { describe, expect, test } from "bun:test"
+import { terminalWriter } from "./terminal-writer"
+
+describe("terminalWriter", () => {
+  test("buffers and flushes once per schedule", () => {
+    const calls: string[] = []
+    const scheduled: VoidFunction[] = []
+    const writer = terminalWriter(
+      (data) => calls.push(data),
+      (flush) => scheduled.push(flush),
+    )
+
+    writer.push("a")
+    writer.push("b")
+    writer.push("c")
+
+    expect(calls).toEqual([])
+    expect(scheduled).toHaveLength(1)
+
+    scheduled[0]?.()
+    expect(calls).toEqual(["abc"])
+  })
+
+  test("flush is a no-op when empty", () => {
+    const calls: string[] = []
+    const writer = terminalWriter(
+      (data) => calls.push(data),
+      (flush) => flush(),
+    )
+    writer.flush()
+    expect(calls).toEqual([])
+  })
+})