Add feature to send timeline clip back to Project Files pane (#5663)

[AlhammoudYazan]

Summary

This pull request introduces a new feature based on Issue #5663. It allows users to send a clip from the timeline back to the Project Files pane, either through a right-click action or future drag-and-drop support. This enhancement improves project organization and workflow by making it easier to reuse timeline clips.

Changes Introduced

• Added a placeholder method send_timeline_clip_to_project_files() in main_window.py
• The method checks if the clip’s source path exists in the Project Files pane and adds it if it doesn't
• Prints messages to console for testing feedback

Notes

• This is the initial logic setup. Integration with UI components (e.g., right-click context menu) will follow in future updates.
• Prevents duplicate entries in the Project Files pane

Testing

• Manually triggered the method using a test clip object
• Verified that new entries are added and duplicates are ignored

Related Issue

Fixes #5663

[AlhammoudYazan]

Hi maintainers 👋

This PR addresses Issue #5663 and adds the method to send timeline clips back to the Project Files pane. The logic is in place, and I’m happy to iterate based on your feedback.

Thank you for reviewing!