feat(changelog): update custom model fine-tuning feature description

Author: rstrahan

CHANGELOG.md

@@ -7,7 +7,7 @@ SPDX-License-Identifier: MIT-0
 
 ### Added
 
-- **Custom Model Fine-Tuning** — Fine-tune Amazon Nova models (Lite and Pro) for document classification using your own labeled Test Sets. The end-to-end workflow — validate data, generate training data, train via Bedrock, and deploy an on-demand custom model endpoint — is driven from a new **Custom Models** page in the Web UI. Custom models can then be selected in any configuration version for classification. Available to Admin and Author roles. **Note:** requires deployment in `us-east-1`. See `docs/custom-model-finetuning.md`.
+- **Custom Model Fine-Tuning** — Fine-tune Amazon Nova 2 models (Lite and Pro) for document classification using your own labeled Test Sets. The end-to-end workflow — validate data, generate training data, train via Bedrock, and deploy an on-demand custom model endpoint — is driven from a new **Custom Models** page in the Web UI. Custom models can then be selected in any configuration version for classification. Available to Admin and Author roles. **Note:** currently requires deployment in `us-east-1`. See `docs/custom-model-finetuning.md`.
 
 - **External SAML/OIDC Identity Provider Federation** — Optional support for federating authentication through an external SAML or OIDC identity provider via Amazon Cognito. Enables organizations to use existing enterprise identity providers (PingOne, Okta, Microsoft Entra ID, etc.) for single sign-on. All federation functionality is opt-in through 12 new CloudFormation parameters — leaving them empty results in zero additional resources and identical behavior to existing Cognito-native authentication. See `docs/external-idp.md`.