🔧 chore: revert notify.ts to writeFileSync implementation

Revert to writeFileSync for /dev/tty writes while keeping retry
mechanism and error logging. The openSync/writeSync/closeSync approach
caused complete notification failure in the current environment.

Author: xiaogaozi

src/notify.ts

@@ -1,4 +1,4 @@
-import { openSync, writeSync, closeSync } from "fs"
+import { writeFileSync } from "fs"
 
 const MAX_OSC_LENGTH = 4096
 
@@ -14,9 +14,7 @@ function warpNotify(title: string, body: string): void {
   let lastError: Error | null = null
   for (let attempt = 0; attempt < 3; attempt++) {
     try {
-      const fd = openSync("/dev/tty", "w")
-      writeSync(fd, sequence)
-      closeSync(fd)
+      writeFileSync("/dev/tty", sequence)
       return
     } catch (err) {
       lastError = err as Error

tests/notify.test.ts

@@ -2,15 +2,11 @@ import { describe, it, afterEach, mock } from "bun:test"
 import { expect } from "bun:test"
 import fs from "fs"
 
-const writeSyncSpy = mock(() => {})
-const openSyncSpy = mock(() => 42)
-const closeSyncSpy = mock(() => {})
+const writeFileSyncSpy = mock(() => {})
 
 mock.module("fs", () => ({
   ...fs,
-  openSync: openSyncSpy,
-  writeSync: writeSyncSpy,
-  closeSync: closeSyncSpy,
+  writeFileSync: writeFileSyncSpy,
 }))
 
 const { warpNotify } = await import("../src/notify")
@@ -19,9 +15,7 @@ describe("warpNotify", () => {
   const originalVersion = process.env.WARP_CLI_AGENT_PROTOCOL_VERSION
 
   afterEach(() => {
-    openSyncSpy.mockClear()
-    writeSyncSpy.mockClear()
-    closeSyncSpy.mockClear()
+    writeFileSyncSpy.mockClear()
     if (originalVersion === undefined) {
       delete process.env.WARP_CLI_AGENT_PROTOCOL_VERSION
     } else {
@@ -32,18 +26,16 @@ describe("warpNotify", () => {
   it("skips when WARP_CLI_AGENT_PROTOCOL_VERSION is not set", () => {
     delete process.env.WARP_CLI_AGENT_PROTOCOL_VERSION
     warpNotify("title", "body")
-    expect(openSyncSpy).not.toHaveBeenCalled()
+    expect(writeFileSyncSpy).not.toHaveBeenCalled()
   })
 
   it("writes OSC 777 sequence when Warp declares protocol support", () => {
     process.env.WARP_CLI_AGENT_PROTOCOL_VERSION = "1"
     warpNotify("warp://cli-agent", '{"event":"stop"}')
-    expect(openSyncSpy).toHaveBeenCalledTimes(1)
-    expect(openSyncSpy).toHaveBeenCalledWith("/dev/tty", "w")
-    expect(writeSyncSpy).toHaveBeenCalledTimes(1)
-    expect(closeSyncSpy).toHaveBeenCalledTimes(1)
+    expect(writeFileSyncSpy).toHaveBeenCalledTimes(1)
 
-    const [, data] = writeSyncSpy.mock.calls[0] as [number, string]
+    const [path, data] = writeFileSyncSpy.mock.calls[0] as [string, string]
+    expect(path).toBe("/dev/tty")
     expect(data).toContain("warp://cli-agent")
     expect(data).toContain('{"event":"stop"}')
     expect(data).toMatch(/^\x1b\]777;notify;/)