feat: Implement Convex authentication including sign-in/sign-up UI, Convex client provider, and backend auth functions.

app/auth/page.tsx

@@ -0,0 +1,22 @@
+"use client";
+
+import { SignIn } from "@/components/auth/SignIn";
+import { Authenticated, Unauthenticated, useQuery } from "convex/react";
+import { api } from "@/convex/_generated/api";
+
+export default function AuthPage() {
+    return (
+        <div className="min-h-screen flex items-center justify-center bg-gray-50">
+            <Unauthenticated>
+                <SignIn />
+            </Unauthenticated>
+            <Authenticated>
+                <div className="text-center">
+                    <h1 className="text-2xl font-bold mb-4">You are logged in!</h1>
+                    <p>Redirecting...</p>
+                    {/* You could add a redirect here or a button to go to dashboard */}
+                </div>
+            </Authenticated>
+        </div>
+    );
+}