docs: add HuggingFace token setup instructions to LLM Katan README

Add comprehensive setup section covering HuggingFace token requirements with three authentication methods:
- Environment variable (HUGGINGFACE_HUB_TOKEN)
- CLI login (huggingface-cli login)
- Token file in home directory

Explains why token is needed (private models, rate limits, reliable downloads) and provides direct link to HuggingFace token settings.

Co-Authored-By: Claude <[email protected]>

Author: yossiovadia

e2e-tests/llm-katan/README.md

@@ -20,6 +20,33 @@ A lightweight LLM serving package using FastAPI and HuggingFace transformers, de
 pip install llm-katan
 ```
 
+### Setup
+
+#### HuggingFace Token (Required)
+
+LLM Katan uses HuggingFace transformers to download models. You'll need a HuggingFace token for:
+- Private models
+- Avoiding rate limits
+- Reliable model downloads
+
+**Option 1: Environment Variable**
+```bash
+export HUGGINGFACE_HUB_TOKEN="your_token_here"
+```
+
+**Option 2: Login via CLI**
+```bash
+huggingface-cli login
+```
+
+**Option 3: Token file in home directory**
+```bash
+# Create ~/.cache/huggingface/token file with your token
+echo "your_token_here" > ~/.cache/huggingface/token
+```
+
+**Get your token:** Visit [https://huggingface.co/settings/tokens](https://huggingface.co/settings/tokens)
+
 ### Basic Usage
 
 ```bash