Add interactive setup wizard UI with cypherpunk aesthetic

Features:
- Beautiful 3-step wizard overlay that appears on first launch
- Step 1: Configure data directory and config file path
- Step 2: Add node endpoints (ID, type, metrics URL, RPC URL)
- Step 3: Success screen with confirmation
- Auto-detects if setup is complete via /api/setup/status
- Only shows wizard if system is not initialized
- Persists all configuration via setup API endpoints

UI/UX:
- Cypherpunk-neue design matching dashboard aesthetic
- Animated progress indicator with glowing dots
- Smooth step transitions
- Form validation
- Real-time node list updates
- Success animations on completion
- Mobile-responsive design

Workflow:
1. On first load, checks /api/setup/status
2. If not initialized, shows full-screen wizard overlay
3. Admin configures paths (data dir, config path)
4. Admin adds node endpoints (can add multiple)
5. Completes setup via /api/setup/complete
6. Wizard closes, dashboard loads with real data

This provides a guided onboarding experience for administrators
instead of requiring manual API calls or configuration files.

Author: claude