Created ConfigDisplay component that shows full client configuration
in a scrollable modal window, replacing non-functional clipboard copy.
Benefits:
- Works over SSH sessions (no clipboard API needed)
- Shows complete configuration, not just public key
- Scrollable for long configs with keyboard navigation
- Users can select and copy text directly in terminal
Changes:
- Created internal/tui/components/config-display.go
- Updated detail.go to replace copyPublicKey with loadConfig
- Removed clipboard-related fields and message type
- Updated help text: 'c' now shows config
- Key bindings for scrolling: ↑↓, pgup/pgdn, g/G, Esc/q to close
Fixes: wg-admin-qtb
