[BUG] Cache interceptor returns etag with incorrect syntax

[henry-wang-nzx]

The response header for the etag in packages/open-next/src/core/routing/cacheInterceptor.ts returns an etag of an incorrect syntax.
cacheInterceptor.ts is used when the following config is enabled:

const config = {
  default: {},
  dangerous: {
    enableCacheInterception: true,
  },
} satisfies OpenNextConfig;

Currently it returns etag: <etag_value>, while the correct syntax requires <etag_value> to be surrounded by double quotes: i.e. etag: "<etag_value>".
See https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/ETag#syntax

This causes issues with Cloudfront CDN compression, as it will remove invalid etags after the compression.
See CloudFront Serve compressed files

Suggested fix
packages/open-next/src/core/routing/cacheInterceptor.ts#L61 creates the etag value as:

const etag = hash(body);

Instead it should be replaced with the correct etag syntax:

const etag = `"${hash(body)}"`

The suggested fix has been tested through patching locally and deployment.

Environment: sst@4.14.3, @opennextjs/aws@4.0.3, next@16.2.6