[FEATURE] Add crop command for images

[Maelkiz]

🚀 Feature Request

Add a crop command to simply-edit that allows users to crop images to specified dimensions or regions.

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🎯 Problem / Motivation

Currently, simply-edit supports various image manipulation tasks like flip, rotate, invert, and grayscale conversion. A crop command would expand the toolkit to include a fundamental image editing operation that users frequently need for everyday image tasks.

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💡 Proposed Solution

Implement a crop command that allows users to crop images to specified dimensions or regions. The implementation details, including:

• Command syntax and options
• Crop region specification (e.g., coordinates, dimensions, aspect ratios)
• Default behavior and parameters
• Error handling

...are left to the developer's discretion to determine the best approach for the simply-edit CLI.

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✅ Acceptance Criteria

• Crop command is implemented and functional
• Command integrates seamlessly with the existing simply-edit CLI
• Cropped images can be output in supported formats (PNG, JPG, ICO, SVG)
• Documentation is updated to reflect the new crop command

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🧠 Notes / Context (if applicable)

This feature would complement the existing image manipulation capabilities and provide users with a more complete toolkit for everyday image tasks.