Replace ALB + Lambda architecture with API Gateway REST API + Lambda
using response streaming for SSE support. This provides:
- No VPC required, reducing complexity and cost
- Native streaming support via API Gateway response streaming
- Pay-per-request pricing model
Changes:
- Add Lambda Web Adapter to Dockerfile for streaming support
- Replace BedrockProxy.template with API Gateway configuration
- Update README with new deployment options and latest models
- Update architecture diagram for API Gateway flow
