Fix broken documentation links (closes #1)

Replace dead readthedocs.io link with GitHub README anchor.
Documentation is currently inline in README — dedicated docs site
will be set up in a future release.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: brycewang-stanford

README.md

@@ -214,7 +214,7 @@ pytest
   author={Wang, Bryce},
   year={2025},
   url={https://github.com/brycewang-stanford/statspai},
-  version={0.1.0}
+  version={0.2.0}
 }
 ```
 
@@ -224,4 +224,4 @@ MIT License. See [LICENSE](LICENSE).
 
 ---
 
-[GitHub](https://github.com/brycewang-stanford/statspai) · [PyPI](https://pypi.org/project/StatsPAI/) · [Documentation](https://statspai.readthedocs.io/) · [CoPaper.AI](https://copaper.ai)
+[GitHub](https://github.com/brycewang-stanford/statspai) · [PyPI](https://pypi.org/project/StatsPAI/) · [User Guide](https://github.com/brycewang-stanford/statspai#quick-example) · [CoPaper.AI](https://copaper.ai)

pyproject.toml

@@ -74,7 +74,7 @@ plotting = [
 
 [project.urls]
 Homepage = "https://github.com/brycewang-stanford/statspai"
-Documentation = "https://statspai.readthedocs.io/"
+Documentation = "https://github.com/brycewang-stanford/statspai#quick-example"
 Repository = "https://github.com/brycewang-stanford/statspai"
 "Bug Reports" = "https://github.com/brycewang-stanford/statspai/issues"