Add simple_document_agent project to RAG & Document Processing category

[rushabh2390]

Summary

• Added my open-source local document processor agent to the Awesome repository list.

Section

• Added under RAG & Document Processing section in README.md.

Checklist

• I placed the entry in the most appropriate category
• I verified the project or resource link works
• If this is a GitHub repository, it is not archived
• If this is a Community Project, it has recent activity and is not stale
• I followed the formatting style used in the README
• I updated related badges, descriptions, or section placement if needed

Notes

• The project uses local Ollama models for offline execution and supports both structured (CSV, XLSX) and unstructured (PDF, MD, TXT) document parsing.