Show disk usage in image list

[amarkdotdev]

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Motivation and Context

container image list did not include disk usage in the default table output. This adds a DISK USAGE column using the same per-variant size data already used by verbose image listing, while excluding attestation manifests reported with the unknown/unknown platform.

Fixes #1712

Testing

• Tested locally
• Added/updated tests
• Added/updated docs

Validation run locally:

• swift test --filter ContainerCommandsTests

[jglogan]

@amarkdotdev thanks for the PR! If this addition reports the same value as that of the FULL SIZE column reported with --verbose, perhaps we should label the columns identically for both non-verbose and verbose usage?

If the value is a reasonable approximation of disk usage, I prefer what you have – DISK USAGE – to FULL SIZE.

[amarkdotdev]

Thanks, that makes sense. This value is not exactly the same shape as the verbose FULL SIZE column: verbose output emits one row per platform variant, while the default table has one row per image reference and aggregates the non-attestation variant sizes for that image. Given that, I think DISK USAGE is the clearer label here.

[saehejkang]

@jglogan This PR is related (somewhat) to the changes here and is been ready for a final ✅ . Just wanted to bring it to your inbox, in case there is overlap here.