Images to 3D head

# 1. Open a session — returns an avatar id and photo upload URLs
curl -X POST https://api.cloud.keentools.io/v1/avatar/init \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "image_count": 5 }'

# 2. Upload each photo to its pre-signed URL
curl -X PUT "$UPLOAD_URL" \
  -H "Content-Type: image/jpeg" \
  --data-binary @photo-1.jpg

# 3. Start reconstruction on the session
curl -X POST https://api.cloud.keentools.io/v1/avatar/$AVATAR_ID/process \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "focal_length_type": { "focal_length_type": "estimate_common" } }'

# 4. Download the result — OBJ + texture, delivered as a ZIP
curl -L -X GET "https://api.cloud.keentools.io/v1/avatar/$AVATAR_ID/get-3d-model?mesh_format=obj&texture=jpg" \
  -H "Authorization: Bearer $API_KEY" \
  -o head.zip