This PR adds native Transformers support alongside the existing reference checkpoint:
- `model.safetensors` + `config.json` — DINOv3ViT-compatible weights converted from `model.pt` (LingBot-Vision backbones are architecturally identical to the DINOv3 ViT implementation in `transformers >= 4.56`), loadable via `AutoModel.from_pretrained(...)` with no custom code
- `preprocessor_config.json` — 512x512 bilinear resize + ImageNet normalization, matching the reference preprocessing
- `README.md` — `library_name: transformers`, a Transformers usage snippet, dual-format wording (also fixes the stale `lbot_vision_infer` import in the existing snippet)
`model.pt` is unchanged and the reference `lingbot_vision` loader is unaffected.
**Verification**: converted weights are numerically equivalent to `model.pt` under the reference implementation (fp32, CPU): max |diff| = 7e-6 on patch/CLS tokens, including non-square inputs (dynamic RoPE). Load path tested on `transformers` 4.56.0 and 5.5.3. Con…
