Fix opening OmaSettings from hosted bar widgets

[tumbleweedlabs]

Summary

• keep direct service calls when OmaSettings is rendered in a normal bar slot
• fall back to the existing omasettings IPC target when another plugin hosts the widget
• preserve show, showPage, hide, open, close, and toggle behavior across both placements

Why

Omarchy now scopes the shell facade exposed to third-party plugins. When a bar-widget manager instantiates OmaSettings, the inherited facade belongs to the manager, so serviceFor cannot return the OmaSettings service. The service remains available through its public IPC target, which provides a plugin-only compatibility path without weakening the host permission boundary.

Testing

• omarchy plugin validate .
• Qt 6 qmllint completed with exit code 0; reported only the existing dynamic facade type warnings
• installed the patched Panel.qml locally
• hosted OmaSettings inside Menubar Manager and confirmed the bar button opens it
• confirmed the shell continued responding to IPC and produced no new OmaSettings diagnostics