- Remove verbose print statements from Lambda handler
- Add dependabot pip entry for oss-index-creator
- Update README with new Lambda and deployed stack state
The Bedrock Knowledge Base creation was failing with 403/404 because
the OpenSearch Serverless data access policy hadn't propagated before
the KB tried to connect. Adds a CDK Custom Resource (using opensearch-py)
that creates the vector index with retry logic, ensuring the full
dependency chain: Collection → DataAccessPolicy → Index → KnowledgeBase.