[Phase 2] Modal Plugin

[prosdev]

Description

Implement modal plugin with full accessibility support (focus trap, ARIA, keyboard handling) for high-attention experiences like exit intent.

Tasks

• Create packages/plugins/src/modal/ directory structure
• Define TypeScript types (types.ts)
• Implement core modal plugin (modal.ts)
  • Overlay/backdrop rendering
  • Dialog content rendering
  • Focus trap implementation
  • Keyboard event handlers (Escape, Tab)
  • ARIA attribute management
• Add default CSS styles
• Export from packages/plugins/src/index.ts
• Auto-register in packages/core/src/runtime.ts

Acceptance Criteria

• Modal renders with overlay backdrop
• Focus trap works (Tab cycles within modal)
• Escape key closes modal
• Backdrop click closes modal (configurable)
• ARIA attributes present (role="dialog", aria-modal="true")
• First focusable element receives focus on open
• Focus returns to trigger element on close
• Mobile responsive
• Body scroll prevented when modal open
• Multiple modals supported
• Emits standard events (shown, action, dismissed)

Estimate: 2 days