Add RTL (Right-to-Left) support for Arabic interface

## Description

PR #4916 successfully added Arabic translations to ComfyUI. However, Arabic is a right-to-left (RTL) language, and the current interface remains left-to-right, which creates an awkward reading experience for Arabic users.

## Current Status

Arabic translations are implemented and working, but the UI layout and text alignment remain optimized for LTR languages.

## Proposed Enhancement

Implement proper RTL support when Arabic is selected as the interface language. This would include:

- Dynamic RTL layout switching based on selected language
- Mirrored UI components (navigation, sidebars, button groups)
- Proper text alignment for RTL reading flow
- Adjusted positioning for dropdowns, tooltips, and context menus
- Special handling for the node editor canvas if needed

## Technical Considerations

Modern CSS approaches like logical properties (`margin-inline-start`, `padding-inline-end`) could be used to minimize the need for separate RTL stylesheets. Alternatively, PostCSS RTL plugins or dedicated RTL CSS could be implemented.

## Expected Outcome

When Arabic is selected, the entire interface should flip to provide a natural right-to-left reading and interaction experience, matching user expectations for Arabic interfaces.

## References

- Original translation PR: #4916
- [MDN: CSS Logical Properties](https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Logical_Properties)
- [Material Design RTL Guidelines](https://m2.material.io/design/usability/bidirectionality.html)

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-4937-Add-RTL-Right-to-Left-support-for-Arabic-interface-24d6d73d365081209421d057379921f5) by [Unito](https://www.unito.io)