Properly Implement MIME Type Validation for 3D Input Formats

[simarjot0032]

We maintain a list of supported 3D input formats in backend/src/constants/formats.ts (e.g., obj, stl, ply, glb, fbx, etc.). Previously, MIME type validation was implemented but removed because it was failing due to improper or missing MIME data for certain formats.

A suggestion was made to use existing MIME type libraries to properly type-secure these objects instead of relying solely on extensions.

Problem

• MIME validation is currently disabled.
• Validation relies only on file extensions.
• This may introduce security risks or incorrect file acceptance.
• Some 3D formats do not have standardized or widely supported MIME types.