Persistent "503 Service Unavailable: no backend" error on Windows 11 23H2

### What is the issue?

Experiencing persistent "503 Service Unavailable: no backend" error when running any Tailscale CLI commands on Windows 11. The Windows service shows as RUNNING but CLI cannot communicate with the backend daemon. Manual debug mode reveals named pipe access denied error:

`safesocket.Listen: namedpipe.Listen: open \\.\pipe\ProtectedPrefix\Administrators\Tailscale\tailscaled: Access is denied.`

All CLI commands (tailscale status, tailscale up, etc.) fail with: "failed to connect to local tailscaled (which appears to be running as tailscaled.exe, pid XXXX). Got error: 503 Service Unavailable: no backend"

### Steps to reproduce

1. Install Tailscale on Windows 11 23H2 (Build 22631.5335) using any method (EXE, MSI, winget)
2. Service starts successfully and shows as RUNNING in sc query Tailscale
3. Run tailscale status or any CLI command
4. Observe "503 Service Unavailable: no backend" error
5. Run tailscaled.exe --verbose=2 --debug=localhost:8080 to see named pipe access denied error

### Are there any recent changes that introduced the issue?

Fresh Windows 11 installation. Issue persists from first Tailscale installation attempt. No changes made - this appears to be a Windows 11 23H2 compatibility issue with Tailscale's named pipe communication mechanism.

**Extensive troubleshooting already attempted:**

- Complete uninstall/reinstall (multiple times with different methods)
- Network stack reset (netsh winsock reset, netsh int ip reset)
- Time synchronization fixes
- Service recreation with proper dependencies and LocalSystem account
- Registry cleanup of Tailscale entries
- VMware/WireGuard/ZeroTier driver removal
- MSI installer instead of EXE
- Update to unstable track (1.85.39)
- Manual debug mode analysis

This appears to be related to Windows 11's enhanced security model affecting named pipe permissions. The core issue is that while the tailscaled.exe service runs successfully, the CLI cannot establish communication over the named pipe due to access restrictions. This may be related to the ProtectedPrefix namespace changes in Windows 11.
Similar issues reported in #10321, #9653, and #13494 but no definitive solution provided. This seems to be an architectural compatibility issue between Tailscale's IPC mechanism and Windows 11's security enhancements.

### OS

Windows

### OS version

Windows 11 Version 23H2 (OS Build 22631.5335)

### Tailscale version

1.85.39

### Other software

_No response_

### Bug report

_No response_