signing-in-to-aws

Gets AWS credentials for CLI/SDK access via `aws login`. Activates when a developer needs to authenticate to AWS for local development, when an AWS operation fails due to missing or expired credentials, or when someone asks about setting up AWS access. Triggers: "set up AWS", "configure AWS", "aws login", "get credentials", "authenticate", "session expired", "token expired", "no credentials", "AccessDeniedException" with no configured credentials.