CLI: Fix image import to output the image ID, allow untagged images, and support --no-trunc

[dkbennett]

Summary of the Pull Request

This PR fixes three related bugs with wslc image import, all of which align it with the equivalent Docker command.

1. Display image ID on stdout after import

Docker CLI outputs the imported image's ID to stdout. We now do the same — the server captures the ID from Docker's API response (via the status field) and returns it through a new [out] LPSTR* ImageId parameter on ImportImage. The CLI displays it truncated to 12 hex chars (matching Docker's default), with sha256: prefix stripped.

2. Allow untagged image imports (empty/null image name)

Docker allows docker import file.tar without specifying a repository:tag, creating a : image. We now support the same — ImageName is [in, unique] (nullable) in the IDL, and the server passes empty repo/tag to the Docker API when no name is provided.

3. Add --no-trunc support for import ID output

Added ArgType::NoTrunc to the import command's arguments. When passed, the full image ID is output instead of the 12-char truncated form.

PR Checklist

• Closes: Link to issue #xxx
• Communication: I've discussed this with core contributors already. If work hasn't been agreed, this work might be rejected
• Tests: Added/updated if needed and all pass
• Localization: All end user facing strings can be localized
• Dev docs: Added/updated if needed
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed

• Updated tests to verify image output trunc, and no trunc
• Enabled the previously skipped untagged image to now work and improved it a bit to validate a few more things.

[Copilot]

Pull request overview

This PR aligns wslc image import behavior with Docker by returning/printing the imported image’s ID, allowing imports without a tag (creating an untagged image), and adding --no-trunc support for full-length ID output.

Changes:

• Extended the service ImportImage COM API to accept a nullable image name and return the imported image ID.
• Updated the CLI import task to print the (optionally truncated) image ID on success and added --no-trunc to image import.
• Updated Windows unit/e2e tests for import output, --no-trunc, and untagged import behavior.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
test/windows/WSLCTests.cpp	Updates COM test calls to pass the new ImageId out-parameter.
test/windows/wslc/e2e/WSLCE2EImageImportTests.cpp	Adds e2e assertions for import ID output (trunc/no-trunc) and untagged import behavior.
src/windows/wslcsession/WSLCSession.h	Updates WSLCSession ImportImage signatures and changes ImportImageImpl to return an ID string.
src/windows/wslcsession/WSLCSession.cpp	Implements optional image name handling, captures/returns image ID from Docker progress, and plumbs it back via [out] LPSTR*.
src/windows/WslcSDK/wslcsdk.cpp	Updates SDK wrapper to satisfy the new COM ImportImage signature by providing an out parameter.
src/windows/wslc/tasks/ImageTasks.cpp	Prints the imported image ID and honors --no-trunc.
src/windows/wslc/services/ImageService.h	Changes ImageService::Import to return the imported image ID.
src/windows/wslc/services/ImageService.cpp	Plumbs through the ImportImage out-parameter and returns the ID to callers.
src/windows/wslc/commands/ImageImportCommand.cpp	Adds ArgType::NoTrunc to the image import command arguments.
src/windows/service/inc/WSLCCompat.idl	Extends compat ImportImage signature to return ImageId.
src/windows/service/inc/wslc.idl	Extends IWSLCSession::ImportImage signature to return ImageId.

[Copilot]

Pull request overview

Copilot reviewed 11 out of 11 changed files in this pull request and generated 7 comments.

[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 5 comments.

[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.

[OneBlue]

LGTM, minor comments

[OneBlue]

LGTM. Minor comment

[Copilot]

Pull request overview

Copilot reviewed 13 out of 13 changed files in this pull request and generated 3 comments.