imagetools: inspect only displays descriptor annotations

Contributing guidelines

• I've read the contributing guidelines and wholeheartedly agree

I've found a bug and checked that ...

• ... the documentation does not mention anything about my problem
• ... there are no open or closed issues that are related to my problem

Description

• The pretty format of imagetools inspect IMAGE doesn't show annotations on the index-level, only descriptors. They are only shown if you use --raw
• Annotations on the manifest-level (imagetools inspect IMAGE@DIGEST) are also not shown (only with --raw)

Expected behaviour

I expected to be able to see all annotations in the pretty/default output format as I can see with --raw

Actual behaviour

Only annotations on the index are shown

Buildx version

github.com/docker/buildx v0.12.0-desktop.2 c5a13b51c1ae9358eb691e9a21c955590e26d0a0

Docker info

No response

Builders list

n/a

Configuration

target "default" {
	tags = ["davidkarlsson416/build:annotations"]
	output = ["type=registry"]
	annotations = [
		"index:foo=bar",
		"manifest:baz=quux",
	]
}

$ docker buildx bake
$ docker buildx imagetools inspect --raw davidkarlsson416/build:annotations | jq '.annotations'
{
  "foo": "bar"
}
$ docker buildx imagetools inspect davidkarlsson416/build:annotations 
Name:      docker.io/davidkarlsson416/build:annotations
MediaType: application/vnd.oci.image.index.v1+json
Digest:    sha256:6e65bf3f63fda02126dcc3bad87a81f686d579f9f70c00b852cd36e537d0e4c4
           
Manifests: 
  Name:        docker.io/davidkarlsson416/build:annotations@sha256:d287b4eced51b94f6dd1ab8617629828273ac11e642d4de3fc00ecdf6b8e900b
  MediaType:   application/vnd.oci.image.manifest.v1+json
  Platform:    linux/arm64
               
  Name:        docker.io/davidkarlsson416/build:annotations@sha256:36777ce0220f8ab9ac9927ec14c71d3d39a8ed3fa7b23b02d827cdbc53b5fe89
  MediaType:   application/vnd.oci.image.manifest.v1+json
  Platform:    unknown/unknown
  Annotations: 
    vnd.docker.reference.digest: sha256:d287b4eced51b94f6dd1ab8617629828273ac11e642d4de3fc00ecdf6b8e900b
    vnd.docker.reference.type:   attestation-manifest
$ docker buildx imagetools inspect --raw docker.io/davidkarlsson416/build:annotations@sha256:d287b4eced51b94f6dd1ab8617629828273ac11e642d4de3fc00ecdf6b8e900b | jq '.annotations'
{
  "baz": "quux"
}
$ docker buildx imagetools inspect docker.io/davidkarlsson416/build:annotations@sha256:d287b4eced51b94f6dd1ab8617629828273ac11e642d4de3fc00ecdf6b8e900b      
Name:      docker.io/davidkarlsson416/build:annotations@sha256:d287b4eced51b94f6dd1ab8617629828273ac11e642d4de3fc00ecdf6b8e900b
MediaType: application/vnd.oci.image.manifest.v1+json
Digest:    sha256:d287b4eced51b94f6dd1ab8617629828273ac11e642d4de3fc00ecdf6b8e900b

Build logs

No response

Additional info

No response

Start by reproducing the issue with the docker buildx imagetools inspect commands and annotation configuration shown above. Trace the imagetools inspect entry point and its existing output tests, then ensure the default output includes index- and manifest-level annotations, while preserving the current --raw behavior.