update:add PEK model download readme

magic_pdf/resources/models/README.md

+#### Install Git LFS
+Before you begin, make sure Git Large File Storage (Git LFS) is installed on your system. Install it using the following command:
+
+```bash
+git lfs install
+```
+
+#### Download the Model from Hugging Face
+To download the `PDF-Extract-Kit` model from Hugging Face, use the following command:
+
+```bash
+git lfs clone https://huggingface.co/wanderkid/PDF-Extract-Kit
+```
+
+Ensure that Git LFS is enabled during the clone to properly download all large files.
+
+
+
+Put [model files]() here:
+
+```
+./
+├── Layout
+│   ├── config.json
+│   └── model_final.pth
+├── MFD
+│   └── weights.pt
+├── MFR
+│   └── UniMERNet
+│       ├── config.json
+│       ├── preprocessor_config.json
+│       ├── pytorch_model.bin
+│       ├── README.md
+│       ├── tokenizer_config.json
+│       └── tokenizer.json
+└── README.md
+```
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