feat(app): migrate from pages router to app router

app/not-found.tsx

@@ -0,0 +1,55 @@
+import Link from "next/link";
+
+export default function NotFound() {
+  return (
+    <>
+      <section
+        className="breadcrumb-wrapper fix bg-cover"
+        style={{
+          backgroundImage: "url(/assets/img/inner-page/breadcrumb.jpg)",
+        }}
+      >
+        <div className="shape">
+          <img src="/assets/img/inner-page/shape.png" alt="img" />
+        </div>
+        <div className="container">
+          <div className="page-heading">
+            <h1 className="breadcrumb-title">Page Not Found</h1>
+            <ul className="breadcrumb-list">
+              <li>
+                <Link href="/">Home</Link>
+              </li>
+              <li>
+                <i className="fa-solid fa-chevron-right"></i>
+              </li>
+              <li>
+                <a href="#">Not Found</a>
+              </li>
+            </ul>
+          </div>
+        </div>
+      </section>
+
+      <section className="section-padding">
+        <div className="container">
+          <div className="row justify-content-center">
+            <div className="col-lg-8 text-center">
+              <div className="error-content">
+                <h2 className="mb-3">404 - Page Not Found</h2>
+                <p className="mb-4">
+                  The page you're looking for could not be found. It may have been moved or deleted. Please check the URL or return to the home page.
+                </p>
+                <div className="button-group">
+                  <Link href="/" className="theme-btn">
+                    Back to Home
+                    <i className="fa-solid fa-arrow-right"></i>
+                  </Link>
+                </div>
+              </div>
+            </div>
+          </div>
+        </div>
+      </section>
+    </>
+  );
+}