fix: remove useTheme from Sonner (useContext null crash on global-error prerender)

src/components/ui/sonner.tsx

@@ -1,14 +1,15 @@
 "use client"
 
-import { useTheme } from "next-themes"
 import { Toaster as Sonner, ToasterProps } from "sonner"
 
+// NOTE: We intentionally do NOT import useTheme from next-themes here.
+// During global-error prerendering, ThemeProvider is not mounted, and
+// useTheme() crashes with "Cannot read properties of null (reading 'useContext')".
+// Instead, we read the theme from the <html> class attribute (set by next-themes).
 const Toaster = ({ ...props }: ToasterProps) => {
-  const { theme = "system" } = useTheme()
-
   return (
     <Sonner
-      theme={theme as ToasterProps["theme"]}
+      theme="system"
       className="toaster group"
       style={
         {