Remove admin routes and components

[Dustin-Reyes]

Delete all admin-related code to simplify the application.

Tasks:

• Remove /admin route from App.jsx
• Delete src/components/admin/ directory
• Remove Dashboard lazy import
• Remove RequireAuth component usage
• Clean up related imports

Acceptance Criteria:

• No admin routes exist
• No admin components in codebase
• App runs without errors
• No broken imports

Sprint: 1 - Clean Up & Structure