fix: handle folder rename with nested items correctly

[Imran-S-heikh]

Issue

Renaming a folder with nested files or subfolders caused the app to crash due to outdated hardcoded paths.

Fix

• Recursively updated all nested path values when a folder is renamed.
• Preserved file contents and updated affected tabs and current file references.

Result

The app no longer crashes when renaming folders containing nested items.

[Imran-S-heikh]

Hi 👋
This is my first open-source contribution — I’m really excited to contribute to Solang!
Please let me know if there’s anything I should improve or adjust. 😊