implement auth error page and moved auth-related pages to /auth path

src/app/auth/signout/page.tsx

@@ -0,0 +1,49 @@
+import { signOut, auth } from "@/auth"
+import { Button } from "@/components/ui/button"
+import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card"
+import { redirect } from "next/navigation"
+import Link from "next/link"
+
+export default async function SignOutPage() {
+  const session = await auth()
+  
+  if (!session) {
+    redirect("/")
+  }
+
+  return (
+    <div className="min-h-screen flex items-center justify-center bg-background p-4">
+      <Card className="w-full max-w-md">
+        <CardHeader className="text-center">
+          <CardTitle className="text-2xl font-bold">Sign Out</CardTitle>
+          <CardDescription>
+            Are you sure you want to sign out?
+          </CardDescription>
+        </CardHeader>
+        <CardContent className="space-y-4">
+          <div className="text-center p-3 bg-muted rounded-lg">
+            <div className="text-sm text-muted-foreground">Currently signed in as</div>
+            <div className="font-medium">{session.user?.name || session.user?.email}</div>
+          </div>
+          
+          <div className="grid grid-cols-2 gap-3">
+            <form
+              action={async () => {
+                "use server"
+                await signOut({ redirectTo: "/" })
+              }}
+            >
+              <Button type="submit" variant="destructive" className="w-full">
+                Sign Out
+              </Button>
+            </form>
+            
+            <Button variant="outline" asChild>
+              <Link href="/">Cancel</Link>
+            </Button>
+          </div>
+        </CardContent>
+      </Card>
+    </div>
+  )
+}