refactor(ui): Refactor ct-image-input to extend ct-file-input

Convert ct-image-input from standalone component to subclass of ct-file-input.
Changes:
- Extends CTFileInput instead of BaseElement
- ImageData now extends FileData
- Compression logic moved to override methods
- Image dimension extraction in processFile override
- Capture attribute added via renderFileInput override
- Backward compatibility maintained via property aliases (images/maxImages)
- Event details include both 'images' and 'files' properties

This reduces code duplication and establishes clear inheritance hierarchy
while maintaining full backward compatibility with existing code.

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Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

Author: 3 people