docs: Add CHANGELOG.md reference to README for better team collaboration

- Add Development Progress section in README
- Reference CHANGELOG.md for detailed development tracking
- Improve team alignment on project progress and technical decisions

README.md

@@ -48,6 +48,18 @@ pytest
 
 Current tests cover the basic application endpoints (`/health` and `/`). As we implement more features (ingestion, embeddings, RAG, chat API), we will add tests for those components following TDD.
 
+## Development Progress
+
+For detailed development progress, implementation decisions, and technical changes, see [`CHANGELOG.md`](./CHANGELOG.md). The changelog provides:
+
+- Chronological development history
+- Technical implementation details  
+- Test results and coverage metrics
+- Component integration status
+- Performance benchmarks and optimization notes
+
+This helps team members stay aligned on project progress and understand the evolution of the codebase.
+
 ## CI/CD and Deployment
 
 This repository includes a GitHub Actions workflow that runs tests on push and pull requests. After merging to `main`, the workflow triggers a Render deploy and runs a post-deploy smoke test against `/health`.