### System details

- Omarchy: `4.0.0.r6807.g902fd8a-1`
- Kernel: `7.2.8-5-omarchy-bore`
- CPU: Intel Core i5-8250U
- GPU: Intel UHD Graphics 620 (`i915`)
- Quickshell before update: `0.3.1-1`
- Qt before update: `qt6-base 6.11.2-3`, `qt6-declarative 6.11.2-2`
- Qt after update: `qt6-base 6.12.0-2`, `qt6-declarative 6.12.0-1`, `qt6-svg 6.12.0-1`, `qt6-wayland 6.12.0-1`

### What happened

Immediately after the system update to Qt 6.12, Omarchy Shell stopped rendering correctly. Initially the top bar was effectively gone (only a black line), and `Super+Space` produced a black screen/menu. After rebuilding Quickshell against Qt 6.12 so the shell could start, the bar and menu still rendered black-on-black because all Omarchy theme color roles were undefined.

The active theme was Matte Black, whose generated shell palette was valid (`bar.background = "#121212"`, `bar.text = "#bebebe"`). The problem happened before those values could be consumed and was not theme-specific configuration.

Representative shell log messages:

```text
@plugins/bar/Bar.qml[75:3]: Unable to assign [undefined] to QColor
@plugins/bar/Bar.qml: TypeError: Cannot read property 'background' of undefined
@plugins/bar/Bar.qml: TypeError: Cannot read property 'text' of undefined
@Ui/PanelToolTip.qml: TypeError: Cannot read property 'text' of undefined
plugins/menu/Menu.qml: TypeError: Cannot read property 'background' of undefined
plugins/menu/Menu.qml: TypeError: Cannot read property 'selectedText' of undefined
ipc shell finishThemeIntro failed: TypeError: Property 'loadColors' of object QQuickColor(...) is not a function
plugins/background/Background.qml: TypeError: Property 'loadColors' of object QQuickColor(...) is not a function
```

### Steps to reproduce

1. Start with Omarchy Shell working on Qt 6.11.2 and Quickshell 0.3.1.
2. Upgrade the Qt packages to 6.12.0 through the normal Omarchy/system update.
3. Restart Omarchy Shell or log in again.
4. Observe missing/black bar surfaces and an unusable black `Super+Space` menu.
5. Inspect `journalctl --user -t omarchy-shell`; theme references such as `Color.bar`, `Color.menu`, and `Color.loadColors()` resolve incorrectly or are undefined.

### Expected behavior

The bar, menus, lock screen, notifications, and other shell surfaces should continue loading their colors dynamically from the active Omarchy theme after a Qt update.

### Diagnosis

Qt 6.12 introduced a `Color` QML singleton in `QtQuick`. Omarchy also imports its own `qs.Commons` singleton named `Color` and uses it unqualified throughout the shell. Under Qt 6.12, references are resolving to Qt's `QQuickColor` object instead of Omarchy's theme singleton. That object has Qt color utility methods but no Omarchy properties such as `bar`, `menu`, or `loadColors`, matching the errors above.

Qt documentation: https://doc.qt.io/qt-6.12/qml-qtquick-color.html

There is also a packaging transition issue: the existing Quickshell binary had been built against Qt 6.11.2, so it needed rebuilding for Qt 6.12 before the shell would reliably start. Rebuilding Quickshell alone did not fix the `Color` collision.

### Confirmed workaround

Rolling the complete installed Qt set back to 6.11.2 together with the matching `quickshell 0.3.1-1`, moving the Qt 6.12-generated QML cache aside, and restarting Omarchy Shell restored the dynamic theme colors and `Super+Space` immediately. The restarted process has none of the `QQuickColor`, `loadColors`, or undefined-color errors.

### Suggested fix

Rename the Omarchy singleton to a name that cannot collide (for example `ThemeColors`), or import `qs.Commons` under an alias and qualify its `Color` references. The package transition should also ensure Quickshell is rebuilt against Qt 6.12.