feat: Complete Issue #8 - Detailed Validation Error Reporting and CLI Enhancements

Major Features:
- Implement comprehensive validation error reporting system (Issue #8)
- Add direct CLI access with 'markitect' command
- Create extensive makefile targets for CLI usage
- Enhance schema validation with detailed error collection

Components Added:
- markitect/validation_error.py: ValidationError system with 8 error types
- Enhanced markitect/schema_validator.py: Detailed error reporting methods
- markitect/cli.py: Enhanced with --detailed-errors and --error-format options
- visualize_schema.py: Schema visualization with ASCII and colorful modes
- Comprehensive test suite for validation error reporting

CLI Enhancements:
- Direct 'markitect' command access for all operations
- Makefile targets for typical CLI usage (cli-help, cli-ingest, etc.)
- Support for text, JSON, and markdown error output formats
- Backward compatibility with existing validation functionality

Testing:
- 11 comprehensive tests for Issue #8 validation error reporting
- Tests for schema validation, visualization, and CLI integration
- 100% test coverage for validation error scenarios

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

markitect/parser.py

@@ -1,7 +1,8 @@
 from markdown_it import MarkdownIt
 
 def parse_markdown_to_ast(md_content: str):
-    md = MarkdownIt()
+    # Enable table parsing and other common plugins
+    md = MarkdownIt("commonmark", {"tables": True}).enable(['table'])
     tokens = md.parse(md_content)
     # Convert to a JSON-serializable list of dicts (tokens are objects, so we dict-ify them recursively)
     def token_to_dict(token):