fix(ui): 로고 필터 제거, 메뉴 네비게이션 오류 수정

- Header.css: filter brightness/invert 완전 제거, cursor:pointer 추가
- Header.jsx: 상단 메뉴 클릭 시 첫 하위 페이지 이동, 드롭다운 닫힘 딜레이 200ms
- SolutionPage.jsx: 폴백 라우트 * 추가

frontend/src/components/layout/Header.css

@@ -25,8 +25,8 @@
 }
 
 /* 로고 */
-.logo { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
+.logo { display: flex; align-items: center; gap: 10px; flex-shrink: 0; cursor: pointer; text-decoration: none; }
-.logo img { height: 40px; width: auto; filter: brightness(0) invert(1); }
+.logo img { height: 40px; width: auto; }
 .logo-text { color: #fff; font-size: 20px; font-weight: 700; }
 .logo-text strong { color: var(--accent); }
 

frontend/src/components/layout/Header.jsx

@@ -60,6 +60,7 @@ export default function Header() {
   const [activeMenu,  setActiveMenu]  = useState(null);
   const [mobileOpen,  setMobileOpen]  = useState(false);
   const [member,      setMember]      = useState(null);
+  const closeTimer = React.useRef(null);
   const location = useLocation();
   const navigate = useNavigate();
 
@@ -117,10 +118,11 @@ export default function Header() {
             {MENU.map(menu => (
               <div key={menu.id}
                    className={`nav-item ${isActive(menu) ? 'active' : ''}`}
-                   onMouseEnter={() => setActiveMenu(menu.id)}
+                   onMouseEnter={() => { clearTimeout(closeTimer.current); setActiveMenu(menu.id); }}
-                   onMouseLeave={() => setActiveMenu(null)}>
+                   onMouseLeave={() => { closeTimer.current = setTimeout(() => setActiveMenu(null), 200); }}>
                 <button className="nav-trigger" aria-haspopup="true"
-                        aria-expanded={activeMenu === menu.id}>
+                        aria-expanded={activeMenu === menu.id}
+                        onClick={() => navigate(menu.children[0].path)}>
                   {menu.label}
                 </button>
                 {activeMenu === menu.id && (

frontend/src/pages/SolutionPage.jsx

@@ -287,6 +287,7 @@ export default function SolutionPage() {
       <Route path="erp" element={<ERP />} />
       <Route path="crm" element={<CRM />} />
       <Route path="bi"  element={<BI />} />
+      <Route path="*"   element={<ERP />} />
     </Routes>
   );
 }