added new start page

src/components/landing/Navbar.jsx

@@ -0,0 +1,10 @@
+export default function Navbar({ onLoginClick }) {
+  return (
+    <nav className="nk-nav">
+      <span className="nk-logo">Находка</span>
+      <button className="nk-nav-btn" onClick={onLoginClick}>
+        Войти
+      </button>
+    </nav>
+  );
+}