### System details

Intel i7-12800H, Intel Iris Xe + NVIDIA RTX A1000 Laptop GPU, Omarchy 4.0.4-1, Quickshell 0.3.1-1, Hyprland 0.56.2

### What's wrong?

If `idle.screensaver` or `idle.lock` in `~/.config/omarchy/shell.json` differs from the built-in defaults so that the *first* idle timeout changes, the screensaver and lock never trigger again for the lifetime of the shell. The machine silently stays unlocked.

**Cause:** Quickshell 0.3.1 `IdleMonitor` goes permanently silent when `timeout` is written after creation (upstream: quickshell-mirror/quickshell#938, fix pending in quickshell-mirror/quickshell#1097).

`plugins/services/idle/Service.qml` creates the `IdleMonitor` with `timeout: root.firstIdleTimeoutSeconds`. At startup that evaluates against the built-in defaults (`defaultScreensaverSeconds: 150`, `defaultLockSeconds: 300`, so 150s). Then `shell.json` loads and the binding changes it (e.g. screensaver 600 / lock 1800, so 600s). That runtime write kills the monitor. The same thing happens whenever `shell.json` idle values are edited while the shell is running.

**Steps to reproduce**

1. Set `"idle": { "screensaver": 600, "lock": 1800 }` in `~/.config/omarchy/shell.json`.
2. `omarchy restart shell`.
3. Leave the machine idle for more than 10 minutes. No screensaver, no lock.
4. `quickshell -p /usr/share/omarchy/shell ipc call idle status`: `lastEvent` stays `idle-monitor: active` with a `lastEventAt` from shell startup. No window has `inhibitingIdle`, and no media is playing.

In my case the shell ran from Oct 1 to Oct 7 without a single idle event.

**Isolated repro (no Omarchy involved):**

```qml
import QtQuick
import Quickshell
import Quickshell.Wayland
ShellRoot {
  property int to: 5
  Timer { interval: 1000; running: true; onTriggered: to = 10 }
  IdleMonitor { timeout: to; onIsIdleChanged: console.log("CHANGED idle=" + isIdle) }
  IdleMonitor { timeout: 10; onIsIdleChanged: console.log("CONTROL idle=" + isIdle) }
}
```

Only `CONTROL` fires. Toggling `enabled` false/true after the timeout change revives the monitor.

**Workaround:** `quickshell -p /usr/share/omarchy/shell ipc call idle disable && quickshell -p /usr/share/omarchy/shell ipc call idle enable` after the shell has loaded its config (and after each `shell.json` idle change). I run that from a small user service. After that the screensaver and lock fire normally.

**Possible fixes on the Omarchy side** until Quickshell ships #1097:
- Keep the `IdleMonitor` `enabled: false` until `shell.json` has loaded, or create it in a `Loader` that is re-created when the timeout changes.
- Or toggle `idleMonitor.enabled` off/on in an `onFirstIdleTimeoutSecondsChanged` handler.

Since this silently disables the screen lock, it's a security issue for anyone who changed the idle timeout.