Add RF-DETR models

[jamjamjon]

Object Detection Models

• rfdetr-large-2026 – Large model (2026 release)
• rfdetr-xlarge – Extra-large model
• rfdetr-2xlarge – Double extra-large model

Instance Segmentation Models

• rfdetr-seg-nano – Nano-scale segmentation model
• rfdetr-seg-small – Small segmentation model
• rfdetr-seg-medium – Medium segmentation model
• rfdetr-seg-large – Large segmentation model
• rfdetr-seg-xlarge – Extra-large segmentation model
• rfdetr-seg-2xlarge – Double extra-large segmentation model

NOTE: All models support dynamic batch sizes, except rfdetr-2xlarge.