Refactor audit timeline styles and layout

[EG-Mohamed]

This pull request refactors the history-modal.blade.php view to improve maintainability, accessibility, and dark mode support. The main changes include moving inline CSS custom properties into a <style> block, introducing new CSS classes for event types and value changes (with dark mode styles), and enhancing RTL (right-to-left) language support.

Styling and Maintainability Improvements:

• Moved all CSS custom properties for .audit-timeline from an inline style attribute into a dedicated <style> block for better maintainability and separation of concerns.
• Replaced inline style usage of left with logical properties like inset-inline-start for .audit-timeline, timeline markers, and arrow icons, improving RTL support. [1] [2] [3] [4]

Dark Mode and Accessibility Enhancements:

• Added new CSS classes for audit event types (.audit-event-created, .audit-event-deleted, .audit-event-updated) and value changes (.audit-old-value, .audit-new-value), with specific dark mode styles to improve readability and accessibility in dark themes.
• Updated markup to use these new classes for event badges and value differences, replacing previous inline color styles. [1] [2] [3]

RTL Language Support:

• Improved support for RTL layouts by using logical CSS properties and flipping the audit arrow icon in RTL contexts.

These changes collectively make the audit history modal more maintainable, visually consistent, and accessible across different themes and text directions.