Remove z-index from electron navigation wrapper in App.css to simplify styling and improve layout consistency.

- Updated MessageContext to adjust message positioning in the Electrobun desktop application, ensuring messages clear the custom title bar.
- Introduced a conditional MESSAGE_TOP value based on the desktop environment, improving the user experience for desktop users.

assets/stylesheets/App.css

@@ -105,7 +105,6 @@
 }
 
 .electron-navigation-wrapper {
-  z-index: 10000;
   user-select: none;
   --webkit-user-select: none;
 }

src/components/Dashboard/context/MessageContext.jsx

@@ -1,11 +1,16 @@
 import { createContext, useContext } from 'react'
 import PropTypes from 'prop-types'
 import { message } from 'antd'
+import { isElectrobunDesktop } from '../../../electrobun-bridge'
 
 const MessageContext = createContext()
 
+// antd's default message top is 8px; push messages down an extra 40px in the
+// desktop app so they clear the custom title bar / drag region.
+const MESSAGE_TOP = isElectrobunDesktop() ? 48 : undefined
+
 export const MessageProvider = ({ children }) => {
-  const [msgApi, contextHolder] = message.useMessage()
+  const [msgApi, contextHolder] = message.useMessage({ top: MESSAGE_TOP })
 
   const showMessage = (type, content, options = {}) => {
     return msgApi.open({