feat(editor): add persistent workspace tree and autosaving IDE editor

[Feyzanur25]

Summary

This PR upgrades the /app IDE experience from a static mock into a functional workspace-driven editor.

What changed

• Added a structured workspace tree with nested folders and files
• Added active file selection from the explorer
• Replaced the mock code area with a real editable code editor surface
• Implemented autosave with persisted workspace state using localStorage
• Added quick actions to create new files and folders from the sidebar
• Kept the responsive mobile sidebar/chat behavior intact
• Added component tests for explorer navigation, autosave, and file creation

Technical depth

This change introduces a real client-side workspace state model inside the main IDE screen. I implemented recursive tree rendering, immutable updates for nested file structures, autosave timing, hydration-safe localStorage persistence, and editor synchronization between active file state and stored content. This makes the IDE screen interactive and significantly closer to a usable coding workspace rather than a static prototype.

Files changed

• pages/app/index.jsx
• tests/components/ide-app.test.tsx

Testing

• Added tests for workspace navigation
• Added tests for autosave persistence
• Added tests for new file creation

Note: I could not fully execute the Jest suite in this environment because project dependencies are not installed (node_modules is missing), but the test coverage for the new behavior has been added.

Hi maintainers, this PR is ready for review. GitHub Actions appears to be waiting for maintainer approval because it comes from a fork. Please approve the workflows when convenient.

[Atharv777]

Hey @Feyzanur25 , Can you share the screenshots of the updated editor UI?