feat: Add validation layer for parsed AST (closes #16)

[akonan]

Summary

This PR implements the validation layer for the parsed AST as described in issue #16. The implementation provides comprehensive validation with clear, actionable error messages and full backward compatibility.

What's Included

• ✅ Enhanced validation for all 40+ component types
• ✅ Clear, actionable error messages with suggestions for fixes
• ✅ Position tracking (line/column) when available
• ✅ Nested structure validation rules
• ✅ Comprehensive test coverage (17 new tests)
• ✅ Full backward compatibility with existing validation

Key Features

1. Smart Error Messages

• Suggests similar types when typos are detected (e.g., "buton" → "Did you mean: button?")
• Provides helpful context (e.g., "Initialize with {} if no properties are needed")
• Shows position information when available

2. Component Validation

• Validates required properties for each component type
• Checks property value enums (variants, input types, etc.)
• Enforces nested structure rules (e.g., buttons can't contain buttons)

3. Accessibility & Best Practices

• Tables should start with headers
• Links shouldn't contain interactive elements
• Radio groups enforce single selection

Usage

// Use original validation (default)
const errors = validate(ast);

// Use enhanced validation
const errors = validate(ast, { enhanced: true });

Test Plan

• Run npm test - all 488 tests pass
• Run npm run build - builds successfully
• Test enhanced validation with various edge cases
• Verify backward compatibility with existing code

Breaking Changes

None - the enhanced validation is opt-in via options parameter.

Related

• Closes Add validation layer for parsed AST #16

🤖 Generated with Claude Code