Fix/mentor feedback

[Sarvesh-Mishra1981]

No description provided.

[Sarvesh-Mishra1981]

What this PR resolves

This PR addresses the direct feedback provided by the mentors on the initial implementation. It cleans up accidental debug code, properly configures the local environment variables, strictly enforces category validation, and resolves CORS-related issues that were preventing the frontend from communicating with the external block registry.

What's New

• CORS & Network Fixes: Updated backend security settings to properly handle Cross-Origin Resource Sharing so the React frontend can securely fetch external blocks.
• Environment Configuration: Fixed local environment routing so developers can test the marketplace natively on their localhost.
• Cleaned Up Synthesis Code: Removed accidental TTY/console debug lines from the Python synthesis engine that were unintentionally committed.

Files Changed

Backend

• backend/backend/settings.py
  • Updated the CORS_ALLOWED_ORIGINS (and related CORS headers) to resolve network blocking issues.
• backend/staticfiles/synthesis/main.py
  • Reverted/removed the leftover TTY debugging print statements to clean up the synthesis execution logs.

Frontend

• frontend/.env.development
  • Corrected the REACT_APP_BACKEND_HOST environment variable to ensure local testing connects to the correct localhost port.
• frontend/src/components/dialogs/project-info-dialog.tsx
  • Updated the block metadata validation to strictly enforce the allowed categories, preventing users from assigning invalid or unsupported categories to their projects.