docs: update README

Author: zmtomorrow

README.md

@@ -142,9 +142,9 @@ Generated by `okb init`, stored in `.okb/config.yaml`:
 ```yaml
 model: gpt-5.4                   # LLM model (any LiteLLM-supported provider)
 api_key_env: LLM_API_KEY         # Environment variable for LLM API key
-language: en                      # Wiki output language
-pageindex_threshold: 20           # PDF pages threshold for PageIndex
-pageindex_api_key_env: ""                # Env var name for PageIndex Cloud API key (default: auto-detect PAGEINDEX_API_KEY)
+language: en                     # Wiki output language
+pageindex_threshold: 20          # PDF pages threshold for PageIndex
+pageindex_api_key_env: ""        # (Optional) Environment variable for PageIndex Cloud API key 
 ```
 
 ### PageIndex integration
@@ -212,6 +212,14 @@ Contributions are welcome! Please submit a pull request, or open an [issue](http
 
 Apache 2.0. See [LICENSE](LICENSE).
 
-### Acknowledgments
+### Support Us
 
-Inspired by [Andrej Karpathy's LLM Wiki pattern](https://gist.github.com/karpathy/442a6bf555914893e9891c11519de94f). Powered by [PageIndex](https://pageindex.ai/).
+Leave us a star 🌟 if you like our project. Thank you!  
+
+<div>
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