GitLab

- Add new Chinese OCR model (ch_PP-OCRv4_rec_server_doc_infer) for server-side use
- Update language support in app.py to include new Chinese model
- Modify models_config.yml to add new model configuration

- Update model path from 'unimernet_small' to 'unimernet_small_2501' in multiple scripts and configuration files
- This change affects download_models.py, download_models_hf.py, and model_configs.yaml

- Remove YOLO v11 language detection model from model_configs.yaml
- Update language detection utils to use a fixed model path instead of dynamic configuration
- Remove unused model weight parameter for YOLO v11 language detection

Introduce an examples accordion within the Gradio application to provide users with
a selection of sample PDFs for demonstration purposes. The added functionality allows
users to quickly test the PDF conversion feature with various document types.