Add new SageMaker examples: DeepSeek OCR, TRL CLI fine-tuning, Neuron… (#2188)

* Add new SageMaker examples: DeepSeek OCR, TRL CLI fine-tuning, Neuron Agent

- DeepSeek OCR Pipeline on SageMaker Training Jobs (3-stage VLM OCR)
- Fine-Tuning LLMs with TRL CLI on SageMaker (zero-code fine-tuning)
- Deploy an AI Agent on AWS Inferentia2 with SageMaker (Strands + MCP)

Includes assets for OCR pipeline diagrams and MCP settings screenshot.

* Fix image paths in DeepSeek OCR notebook (../assets -> ./assets)

* Remove anchor tags from DeepSeek OCR notebook to fix heading rendering

* Fix notebook issues: container images, trackio docs, use documentation-images

* Update container reference to HF vLLM Inference Neuronx DLC

Author: fgbelidji