Add new reusable components:
- EmptyState: for empty list/search states with icon, title, description
- ErrorState: for error displays with optional retry button
- LoadingState: for loading states with Spinner and message
- PageHeader: for consistent page headers with title, description, actions
Apply components across pages:
- agents, collections, tool-search pages use new state components
- stats page uses LoadingState and ErrorState
- faq page uses Icon for chevrons
- health page uses Table components
- dashboard agent forms use Input, Select, Textarea, Label
- Replace custom div spinners with Spinner component
- Add new Table UI component with rich features (sorting, empty states, interactive rows)
- Create DashboardLayout component with sidebar navigation
- Redesign Agents page with table layout showing provider, tools, and actions
- Redesign Collections page with table layout showing visibility and tool counts
- Add surface-secondary color token for proper dark mode support
- Add home and user icons to icon library
- Fix missing foreground-quaternary with muted color
🤖 Generated with [Claude Code](https://claude.ai/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
