Hono AWS Lambda@Edge Adapter: Repeated Headers Truncated to Single Value

The AWS Lambda@Edge adapter for Hono incorrectly uses `Headers.set` instead of `Headers.append` when writing repeated request headers, causing only the last value to be preserved.

Applications deployed on AWS Lambda@Edge that rely on multi-value request headers such as X-Forwarded-For, Forwarded, or Via.

Review your Lambda@Edge deployments for reliance on repeated header values and apply the fix once available.