Feature/schema soft validation

[litedatum]

1. Extend shared/utils/type_parser.py with desired_type parsing
2. Implement CompatibilityAnalyzer class in cli/commands/schema.py
3. Implement DesiredTypeRuleGenerator class
4. Enhance Phase 2 execution to use generated rules
5. Update ResultMerger to handle desired_type validation results
6. Modify output formatters for new result structure
7. Add comprehensive error handling for all failure scenarios
8. Core validation: Test LENGTH and REGEX rule executors with generated rules
9. Database-specific testing: Focus on MySQL for DATE_FORMAT validation

Resolved #39