feat(vlm): add Nanonets OCR2 onboarding (#3274)

* feat(vlm): add nanonets ocr2 onboarding

Signed-off-by: Georg Heiler <georg.kf.heiler@gmail.com>

* feat(vlm): add vLLM and API runtimes for Nanonets-OCR2

Extend the Nanonets-OCR2 preset with vLLM + remote API paths so all
standard docling runtimes (Transformers, MLX, vLLM, API, LM Studio,
OpenAI-compatible) work out of the box. Drop the restricted
supported_engines set to match the GLM-OCR / LightOnOCR / Falcon-OCR
pattern, add top-level torch_dtype on the Transformers override, and
register NANONETS_OCR2_VLLM / NANONETS_OCR2_VLLM_API /
NANONETS_OCR2_LMSTUDIO_API legacy specs plus VlmModelType enum entries.

Folds in the remote-API scope that was on the superseded PR #3275.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Georg Heiler <georg.kf.heiler@gmail.com>

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Signed-off-by: Georg Heiler <georg.kf.heiler@gmail.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>