fix: prevent flickering by removing auto color scheme and default background color (#1299)

* fix: prevent flickering by removing auto color scheme and default background color

* fix: typecheck issue

apps/nextjs/src/app/[locale]/_client-providers/mantine.tsx

@@ -16,7 +16,7 @@ export const CustomMantineProvider = ({ children }: PropsWithChildren) => {
   return (
     <DirectionProvider>
       <MantineProvider
-        defaultColorScheme="auto"
+        defaultColorScheme="dark"
         colorSchemeManager={manager}
         theme={createTheme({
           primaryColor: "red",
@@ -62,6 +62,7 @@ function useColorSchemeManager(): MantineColorSchemeManager {
     },
 
     set: (value) => {
+      if (value === "auto") return;
       try {
         if (session) {
           mutateColorScheme({ colorScheme: value });