WEB3-026: Admin Dashboard — Backend APIs

[FuRankLy]

User Story

As an admin, I need backend endpoints to manage members and events.

Description

Admin-only endpoints: list/search members, member detail, remove member, add/remove events from users, dashboard stats, create/delete events. All restricted to admins. Log destructive actions.

Acceptance Criteria

• All endpoints reject non-admins
• Member search by nickname and wallet
• Paginated member list
• Add/remove events works
• Stats endpoint returns correct numbers
• Destructive actions logged
• Create and delete events work

Points: 5 · Blocked By: WEB3-012