feat: Update AWS KB retrieval server with improved credential handling

The commit message captures the key changes made to the AWS Knowledge Base retrieval server:

1. Enhanced credential handling by supporting multiple authentication methods:
   - Explicit AWS access key and secret key
   - AWS profile credentials
   - AWS provider chain (e.g., EC2 IAM roles)

2. Added more robust error logging for credential loading
3. Configured longer timeouts for network requests
4. Updated dependencies to support new credential providers

The changes improve the flexibility and reliability of AWS credential management in the server.

Author: zxkane