## What happened

`omarchy plugin clone omarchy.bar` produces a clone and switches to it, but the bar layer surface then fails to render on **any** monitor, even with zero edits to the cloned file.

## Expected

Cloning `omarchy.bar` (per the documented "clone to customize" workflow) should produce a working, editable copy of the bar, same as cloning a bar-widget plugin (e.g. `omarchy.workspaces`) does.

## Steps to reproduce

1. `omarchy plugin clone omarchy.bar`
2. `omarchy restart shell`
3. `hyprctl layers` — no `omarchy-bar` namespace layer appears on any monitor.

No edits to the cloned `Bar.qml` are needed to reproduce this.

## Root cause (found while investigating)

In `shell.qml`, the custom-bar path (`pluginBarLoader`, a `Loader { source: ... }`) instantiates the `Bar` component from a URL, then only assigns `omarchyPath` / `barConfig` / `barWidgetRegistry` afterward, in `onLoaded: shell.configureBar(item, ...)`. But `Bar.qml` declares these three as `required property`. Required properties need to be supplied at construction time; assigning them after `onLoaded` is too late, so QML logs "Required property X was not initialized" for all three and the Bar component fails to instantiate correctly.

The default-bar path (`defaultBarComponent`) works fine because it binds these properties declaratively inline:

```qml
Component {
  id: defaultBarComponent
  Bar {
    omarchyPath: shell.omarchyPath
    barWidgetRegistry: shell.barWidgetRegistry
    barConfig: shell.barConfig
    shell: shell
    manifest: shell.barManifestFor(shell.defaultBarId)
  }
}
```

The custom-bar `Loader` path doesn't have an equivalent way to bind these before/at creation, since `Loader.source` (URL-based) instantiates the component immediately without support for passing initial required properties, unlike `Loader.setSource(url, properties)` or `component.createObject(parent, properties)`.

## Diagnostics

```
$ omarchy version
4.0.1-1
$ hyprctl version
Hyprland 0.56.2, commit efb50993780079460b0cbed1363e2166a2de1d9f
$ uname -r
7.1.9-arch1-2
```

journalctl at the moment of the failure:

```
WARN scene: file:///home/<user>/.config/omarchy/plugins/<user>.bar/Bar.qml[21:3]: Required property omarchyPath was not initialized
WARN scene: file:///home/<user>/.config/omarchy/plugins/<user>.bar/Bar.qml[28:3]: Required property barConfig was not initialized
WARN scene: file:///home/<user>/.config/omarchy/plugins/<user>.bar/Bar.qml[23:3]: Required property barWidgetRegistry was not initialized
WARN scene: @shell.qml[256:-1]: ReferenceError: errorString is not defined
```

(The last line is a secondary bug: `pluginBarLoader.onStatusChanged` calls `errorString()` as a bare function, but it's a method on the `Loader` item — should probably be `pluginBarLoader.errorString()` or similar, since as written it throws `ReferenceError` instead of logging the real load error.)

## Workaround

`omarchy plugin remove <clone-id> --yes` restores `omarchy.bar` cleanly.