Fix/mesh transform plus export

[iammojogo-sudo]

Summary

Keep the mesh transform gizmo usable after a drag and make the Export menu save the mesh as it currently appears in the viewer, including its transforms.

Changes

• Prevent the mesh from being deselected when a gizmo drag ends, so the user can continue translating, rotating, or scaling it.
• Add a reset-transform control for the selected mesh.
• Export the live mesh with its current world transform in GLB, OBJ, STL, and PLY formats.
• Use the mesh’s original materials for export so viewer display modes do not replace them in the exported file.
• Leave point-light behavior unchanged.

Testing

• Manually tested the gizmo and transformed exports in Modly.
• The automated build could not complete in this environment because esbuild was denied access to a directory above the project. The TypeScript check reported unrelated asset-library and workflow errors, with no diagnostics in the changed files.

Files changed

• src/areas/generate/GeneratePage.tsx
• src/areas/generate/components/Viewer3D.tsx

[iammojogo-sudo]

Images are 1: original in Modly, 2: modified transforms in Modly, and then all four file types tested SAT for export with transforms in place.

[iammojogo-sudo]

I also re-included the reset button as well as fixed the gizmo disappearing when mouse release not over mesh.