feat(comfy_api): add basic 3D Model file types

[bigcat88]

This should make possible to properly implement Convert Format nodes (GLB -> FBX, etc.) or pass a 3D model generated by one API service as input to another (e.g., generate with Meshy -> texture with Hunuyan3D Pro)

Changes

• New File3D backing class (comfy_api/latest/_util/geometry_types.py): Stores 3D model data in memory as BytesIO with format metadata
• New ComfyTypes (comfy_api/latest/_io.py):
  • File3DAny - generic 3D file type
  • File3DGLB, File3DGLTF, File3DFBX, File3DOBJ, File3DSTL, File3DUSDZ - format-specific types
• New download_url_to_file_3d helper: task_id optional; when provided, also writes file to disk for backward compatibility
• Updated 3D generation nodes (Meshy, Hunyuan3D): Now return typed File3D outputs alongside existing string paths
• TODO: Update Tripo3D nodes

Backward Compatibility: Existing workflows continue to work - nodes output both the new typed File3D objects and the original string file paths.

API Node PR Checklist

Scope

• Is API Node Change

Pricing & Billing

• Need pricing update
• No pricing update

If Need pricing update:

• Metronome rate cards updated
• Auto‑billing tests updated and passing

QA

• QA done
• QA not required

Comms

• Informed Kosinkadink