feat(auth): enterprise authentication and user management

frontend/athena/app/login/page.tsx

@@ -1,24 +1,20 @@
 "use client";
 
 import { useState } from "react";
-import { useRouter } from "next/navigation";
 
 export default function LoginPage() {
-  const router = useRouter();
-
   const [username, setUsername] = useState("");
   const [password, setPassword] = useState("");
   const [error, setError] = useState("");
 
   async function handleLogin(e: React.FormEvent) {
     e.preventDefault();
+
     setError("");
 
-    const response = await fetch(
-      `${process.env.NEXT_PUBLIC_API_URL}/auth/login`,
-      {
+    try {
+      const response = await fetch("/api/login", {
         method: "POST",
-        credentials: "include",
         headers: {
           "Content-Type": "application/json",
         },
@@ -26,15 +22,20 @@ export default function LoginPage() {
           username,
           password,
         }),
+      });
+
+      const data = await response.json();
+
+      if (response.ok) {
+        window.location.href = "/dashboard";
+        return;
       }
-    );
 
-    if (response.ok) {
-      router.push("/dashboard");
-      return;
+      setError(data.detail ?? "Login fehlgeschlagen");
+    } catch (err) {
+      console.error(err);
+      setError("Technischer Fehler");
     }
-
-    setError("Benutzername oder Passwort ist falsch.");
   }
 
   return (
@@ -63,12 +64,11 @@ export default function LoginPage() {
         />
 
         {error && (
-          <p className="mb-4 text-red-600">
-            {error}
-          </p>
+          <p className="mb-4 text-red-600">{error}</p>
         )}
 
         <button
+          type="submit"
           className="w-full rounded bg-blue-600 p-3 text-white hover:bg-blue-700"
         >
           Anmelden
@@ -76,4 +76,4 @@ export default function LoginPage() {
       </form>
     </main>
   );
-}
+}