Addition of Participant Dashboard.

As a participant i want to be able to manage participation of my events directly from the participant dashboard.

Allowing me (a participant to)
- Join or leave events.
- View and register upcoming events
- View event description

More ideas are welcomed.
@Harsh2509 @vivekrawat21 @manvichaudhary55

No files, tests, or entry points are named. Start by locating the participant dashboard and event-management flows in the TypeScript Next.js/React application, then trace how event participation is handled with Supabase. Done means participants can join or leave events, view and register for upcoming events, and read event descriptions from the dashboard.

索引モデルが issue の本文から書いたものです。