fix(members): restore professor profile image and remove GitHub profile link

- Restore prof_profile.png under refer_landing_page/public/images/
- Remove GitHub Profile link component and separator from professor section

refer_landing_page/app/members/page.tsx

@@ -74,15 +74,6 @@ export default function MembersPage() {
                 >
                   sjkoh@knu.ac.kr
                 </a>
-                <span className="text-ink-mute">|</span>
-                <a
-                  href="https://github.com/sjkoh12"
-                  target="_blank"
-                  rel="noopener noreferrer"
-                  className="text-ink hover:text-cobalt-dark hover:underline"
-                >
-                  GitHub Profile ↗
-                </a>
               </div>
             </div>
             <div className="lg:col-span-4 flex justify-center items-center">