### System details

HP ZBOOK Ultra G1A, RYZEN AI MAX+ Pro 395, Omarchy 3.8.4

### What's wrong?

# Upgrade Bug: Leftover `10-iwd-backend.conf` breaks Wi-Fi on Quattro 4 Beta (migrating from 3.8.4)

### Description
After upgrading from Omarchy 3.8.4 to the Quattro 4 Beta, the wireless interface becomes completely unusable. The system moves from the legacy `iwd` stack to `NetworkManager`, but a stale configuration fragment drops the Wi-Fi card into an unrecoverable `unavailable` / `DOWN` loop. 

### Root Cause
The upgrade process leaves behind the `/etc/NetworkManager/conf.d/10-iwd-backend.conf` file from version 3.8.4. This file explicitly instructs NetworkManager to use `iwd` as its backend. However, because `iwd.service` is purged or deprecated during the Quattro 4 transition, NetworkManager hangs indefinitely waiting for a missing daemon, rendering the wireless hardware unavailable.

### Environment
* **Previous OS Version:** Omarchy 3.8.4
* **Target OS Version:** Omarchy Quattro 4 Beta
* **Network Manager:** NetworkManager (systemd)
* **Affected Hardware Example:** Intel Wireless (e.g., driver mapping to `wlp193s0`)

### Steps to Reproduce
1. Run the system upgrade from Omarchy 3.8.4 to Quattro 4 Beta.
2. Reboot the machine post-upgrade.
3. Check network interface status with `ip a` (shows wireless link as `DOWN`).
4. Check NetworkManager status with `nmcli device status` (shows wireless interface as `unavailable`).

### Diagnostic Outputs (Before Fix)
* Running `systemctl status iwd` returns: 
  ```text
  Unit iwd.service could not be found.
  ```
* Running `nmcli device status` shows:
  ```text
  DEVICE       TYPE      STATE        CONNECTION
  wlp193s0     wifi      unavailable  --
  ```

### Proposed Resolution / Fix for the Upgrade Script
The Quattro 4 upgrade cleanup routine needs to explicitly remove or deprecate old backend configuration fragments. Adding a removal step for the stale configuration file solves the deadlock:

```bash
# Suggested addition to the post-upgrade/migration script
if [ -f /etc/NetworkManager/conf.d/10-iwd-backend.conf ]; then
    rm /etc/NetworkManager/conf.d/10-iwd-backend.conf
fi
```

### Temporary Workaround for Users
Manually deleting the file, enabling the default supplicant, and restarting the network stack resolves the issue immediately:
```bash
sudo rm /etc/NetworkManager/conf.d/10-iwd-backend.conf
sudo systemctl enable --now wpa_supplicant
sudo systemctl restart NetworkManager
sudo ip link set wlp193s0 up
```