feat: add team member modal with descriptions

Click on a team card to see a popup with larger photo, Instagram link,
and personal description. All 13 team members now have descriptions.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/types/content.ts

@@ -9,6 +9,7 @@ export interface TeamMember {
   role: string;
   image: string;
   instagram?: string;
+  description?: string;
 }
 
 export interface ContactInfo {