Feature Request: Add Direct Mask Clear Button to LoadImage Node

## Current Behavior
To clear a mask on LoadImage nodes, users must:
1. Select the node
1. Click the toolbar menu button to open the mask editor
2. Click the "Clear" button in the mask editor
3. Click "Save" to apply changes

## Proposed Enhancement
Add a direct "Clear Mask" button/action to LoadImage nodes that clears the mask without opening the mask editor.

## Use Cases
- Quickly reset masks during workflow iteration
- Batch processing where masks need frequent clearing
- Improved UX for users who frequently clear masks

## Implementation Suggestions
1. **Quick Action Button**: Add a small "×" or "Clear Mask" button in the node UI
2. **Context Menu**: Right-click option on the node
3. **Keyboard Shortcut**: When node is selected
4. **Widget Enhancement**: Extend upload widget with mask operations dropdown

## Benefits
- Reduces clicks from 4 to 1
- Speeds up workflow iteration
- More intuitive for new users
- Consistent with other direct node actions

## Technical Considerations
- Frontend change in ComfyUI_frontend repository
- Maintain compatibility with existing mask editor
- Could be implemented as part of the widget system enhancement

## Additional Context
This feature would significantly improve the workflow for users who work with masks frequently, especially in iterative design processes where masks need to be cleared and redrawn multiple times.

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-4642-Feature-Request-Add-Direct-Mask-Clear-Button-to-LoadImage-Node-2426d73d365081e38eebff934bb9d761) by [Unito](https://www.unito.io)