[ROADMAP] Feature Expansion Roadmap for flk CLI

This parent issue tracks the expansion of the flk CLI tool with new features and improvements. Each sub-issue covers a major planned enhancement.

Planned Enhancements

• Version pinning for packages
• List/show commands for packages
• Package update command
• Flake.lock management commands
• Environment variable management
• Shell script and hook management
• Project template expansion
• Enhanced package info and diff commands
• Export/import configurations
• Multiple flake profiles
• Package groups and presets management
• Shell completion and alias generation

Each feature is described in a sub-issue linked to this parent.