feat: enhance profile page and authentication with user avatar support

- Updated `next.config.ts` to allow images from various external sources, including LinkedIn and GitHub.
- Refactored `ProfilePage` to improve layout and display user avatar, name, and role more prominently.
- Enhanced `AuthButton` to show user avatar if available, improving user experience.
- Updated authentication logic in `auth.ts` to include user avatar and role in session management.
- Extended JWT type definitions to support new user fields (firstName, lastName, avatar, role) for better user data handling.

src/types/next-auth.d.ts

@@ -28,5 +28,9 @@ declare module "next-auth" {
 declare module "next-auth/jwt" {
   interface JWT {
     id: string
+    firstName?: string
+    lastName?: string
+    avatar?: string
+    role: string
   }
 }