Codex desktop app: processes launch but no window ever appears on Windows (26.901.2854.0)

Environment

• OS: Windows 11 (25H2 family), OS build: 26200.9168
• Codex desktop app: OpenAI.Codex_26.901.2854.0_x64__2p2nqsd0c76g0 (display name "ChatGPT" in MSIX), Status Ok
• Codex CLI: 0.153.0 (works fine)
• Web (chatgpt.com): works fine with the same account

Problem

After the app updated to 26.901.2854.0, clicking the desktop icon / Start menu entry starts a batch of ChatGPT.exe processes, but no window is ever created:

• MainWindowHandle stays 0, MainWindowTitle empty (main process + crashpad/gpu/network/storage helpers; no renderer process).
• The main process spins at ~1 full CPU core indefinitely (observed 50-382 s of CPU over a single session).
• Killing the processes and relaunching reproduces it 100% of the time.
• App log (LocalCache\Local\Codex\Logs\...\codex-desktop-*.log) stops after 3 lines:
  • [sparkle] in_app_updates_policy_wait_started timeoutMs=300000
  • Launching app agentRunId=null ... platform=win32
  • Appshot hotkey inactive configured=true enabled=false platform=win32
• Launching the exe with --enable-logging --v=1 reveals the blocking error:

Failed to start the Artifact Session host errorMessage="Artifact Session host Unix-socket transport is not available on Windows." errorName=Error
errorStack="Error: Artifact Session host Unix-socket transport is not available on Windows.
    at e.start (...app.asar\.vite\build\main-CNWtD3f8.js:8:28582)
    at uze (...app.asar\.vite\build\main-CNWtD3f8.js:1526:69057)
    at process.processTicksAndRejections (node:internal/process/task_queues:104:5)
    at async ...app.asar\.vite\build\bootstrap-BaU3O31M.js:134:3802"

• cua_node runtime staging: every launch creates a fresh .staging-8e7585fc8f35ed57-* folder under %LOCALAPPDATA%\OpenAI\Codex\runtimes\cua_node (30+ accumulated) and never finalizes it (no final folder for that hash; only the older e4d75eceaa042f20 exists). Manually creating the final folder with bin + exact manifest.json from the package does NOT change behavior.

What I already tried (none fixed it)

• Kill all processes and relaunch
• --disable-gpu direct exe launch
• Clearing/renaming all cache folders (Cache, Code Cache, ShaderCache, GPUPersistentCache, etc.)
• Reinstall: removed from D:\WindowsApps, installed fresh to C:\Program Files\WindowsApps
• Get-AppxPackage OpenAI.Codex | Reset-AppxPackage
• Fresh profile via empty CODEX_HOME isolation launch
• Manual cua_node runtime finalization (bin + manifest.json)

Expected behavior

The app should open its window and proceed to the sign-in / main interface.

Notes

This looks like a Windows regression in 26.901.2854.0: bootstrap unconditionally starts an "Artifact Session host" that requires a Unix-socket transport which does not exist on Windows. The startup promise never resolves, so the main window is never created and the main process busy-loops.