feat: implement Issue #143 - CLI integration and user experience for asset management

Complete implementation of asset management CLI commands with comprehensive
user experience improvements:

## Core Features
- Asset management commands: add, list, stats, cleanup
- Package management commands: create, extract, list, validate
- Workspace management commands: init, status, sync

## CLI Integration
- Seamless integration with existing markitect CLI patterns
- Consistent Click command group registration
- Professional output formatting with checkmarks and structured details
- Comprehensive help text with examples and feature descriptions

## Code Quality
- Extracted common CLI utilities for consistent UX patterns
- Robust error handling with informative messages
- Configuration integration with sensible defaults
- Path validation and workspace management

## Testing & Quality Assurance
- Comprehensive integration tests covering all command groups
- No regressions in existing CLI functionality
- End-to-end workflow validation
- Production-ready error handling and edge cases

## Documentation
- Enhanced docstrings with usage examples
- Comprehensive --help text for all commands
- Clear argument descriptions and feature highlights

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

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

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+Hello Asset Management!

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