Update architecture diagram references, add changelog entry and contributor

Author: rajat.dogra

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- Updated architecture diagram with latest logos (`docs/architecture-diagram/FAST-architecture-20260403.png`)
+
 ## [0.4.1] - 2026-03-25
 
 ### Added

CONTRIBUTORS.md

@@ -17,4 +17,5 @@
 - Meghana Ashok
 - Suren Gunturu
 - Samaneh Aminikhanghahi
-- Abhilash Balachandran
+- Abhilash Balachandran
+- Rajat Dogra

README.md

@@ -50,7 +50,7 @@ What comes next? That's up to you, the developer. With your requirements in mind
 
 ## Architecture
 
-![Architecture Diagram](docs/architecture-diagram/FAST-architecture-20260302.png)
+![Architecture Diagram](docs/architecture-diagram/FAST-architecture-20260403.png)
 
 The out-of-the-box architecture is shown above. The diagram illustrates the authentication flows across the stack:
 1. User login to the frontend (Cognito User Pool — Authorization Code grant): The user authenticates with Cognito via the web application hosted on AWS Amplify. Cognito issues a JWT access token for the session.