Persian RTL version of Collapse Long Posts

Changes

• Added Persian translation support.
• Added RTL support.
• Simplified the button styling.
• Kept the expand/collapse button centered inside its own post.
• Removed the viewport-centered floating behavior.
• Improved light and dark theme compatibility.

Credits

Original plugin by GatekeeperMaxim.

Persian RTL improvements by https://github.com/idmal

Original plugin page:
https://www.flatbb.com/market/collapse_long_posts

This is an independent community modification.