fix: update constants.ts barrel export and fix MegaDropdownData type safety

src/components/layout/header.tsx

@@ -183,7 +183,7 @@ function HeaderContent() {
                   <MegaDropdown
                     key={item.id}
                     label={item.label}
-                    items={MEGA_DROPDOWN_DATA[item.dropdownKey!]}
+                    items={MEGA_DROPDOWN_DATA[item.dropdownKey!] ?? []}
                     isOpen={openDropdown === item.id}
                     onToggle={() => setOpenDropdown(openDropdown === item.id ? null : item.id)}
                   />

src/lib/constants.ts

@@ -1,7 +1,12 @@
 export {
   COMPANY_INFO,
   NAVIGATION,
+  NAVIGATION_V2,
+  MEGA_DROPDOWN_DATA,
   type NavigationItem,
+  type NavigationItemV2,
+  type MegaDropdownItem,
+  type MegaDropdownData,
   STATS,
   type StatItem,
   SERVICES,
@@ -10,4 +15,8 @@ export {
   type NewsItem,
   type NewsCategory,
   CASES,
+  TEAM_MEMBERS,
+  type TeamMember,
+  METHODOLOGY,
+  type MethodologyPhase,
 } from './constants/index';