CLI: Route wslc warnings through Reporter

[dkbennett]

Summary of the Pull Request

Follows up on #41010 (which routed all non-help wslc output through Reporter) by
routing service-layer warnings through the same Reporter sink. Previously the
warning callback wrote directly to stderr, bypassing Reporter and its
no-color / output-level handling. With this change warnings are now routed as warnings to stderr, colored yellow where supported, and non-colored when not supported or color is disabled.

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

• WarningCallback is now a Reporter adapter. It takes a Reporter& in its
  constructor and its OnWarning forwards the message to m_reporter.Warn(...)
  (verbatim, with color added only on a VT console, and a null-guard), instead of
  fputws(Message, stderr).
• Services build the callback internally from a Reporter&. The methods that
  surface warnings now take a Reporter& and construct WarningCallback locally,
  replacing the Microsoft::WRL::Make<WarningCallback>() COM object that was
  created and passed around:
  • ContainerService — Run / Create / Start (via CreateInternal)
  • ImageService — Load / Import / Pull / Push
  • NetworkService — Create
  • SessionService — OpenOrCreateDefaultSession / Enter
  • VolumeService — Prune
• Call sites simplified. Tasks pass context.Reporter; the floating
  IWarningCallback* parameter is gone.

Why

• Reporter becomes the single output sink for warnings too, so warnings honor
  no-color (SGR stripping) and level-based routing consistently with all other
  CLI output.
• Removes a floating callback pointer threaded through the task/service layers in
  favor of a Reporter&, cleaning up call sites.

Notes

• No public/SDK ABI surface is affected — these are internal CLI service helpers.

Validation Steps Performed

• Forced a test warning and did some manual validation of the output with its expected color, no-color, and redirected output, confirmed it looks as-expected (this is the attached images)
• The E2E tests have WarningCallback for session warnings explicitly tested, which should verify no regressions with the warning plumbing, and these tests passed locally.

[Copilot]

Pull request overview

Routes WSLC CLI service-layer warnings through the existing Reporter output sink so warnings consistently honor --no-color and output-level routing (stderr), instead of writing directly to stderr.

Changes:

• Updated IWarningCallback implementation (WarningCallback) to forward warnings to Reporter::Warn.
• Threaded Reporter& into multiple service entry points (image/network/session/volume/container) and updated task call sites accordingly.
• Replaced direct construction/passing of warning callback COM objects with locally constructed adapters per operation.

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/windows/wslc/tasks/VolumeTasks.cpp	Passes context.Reporter into VolumeService::Prune.
src/windows/wslc/tasks/SessionTasks.cpp	Passes context.Reporter into SessionService::OpenOrCreateDefaultSession.
src/windows/wslc/tasks/NetworkTasks.cpp	Passes context.Reporter into NetworkService::Create.
src/windows/wslc/tasks/ImageTasks.cpp	Passes context.Reporter into ImageService::{Pull,Push,Load,Import}.
src/windows/wslc/services/WarningCallback.h	Converts warnings to Reporter::Warn output.
src/windows/wslc/services/VolumeService.h	Adds Reporter& to Prune signature.
src/windows/wslc/services/VolumeService.cpp	Constructs warning adapter and passes it into PruneVolumes.
src/windows/wslc/services/SessionService.h	Adds Reporter& to OpenOrCreateDefaultSession signature.
src/windows/wslc/services/SessionService.cpp	Constructs warning adapter for CreateSession/EnterSession.
src/windows/wslc/services/NetworkService.h	Adds Reporter& to Create signature.
src/windows/wslc/services/NetworkService.cpp	Constructs warning adapter and passes it into CreateNetwork.
src/windows/wslc/services/ImageService.h	Adds Reporter& to Load/Import/Pull/Push signatures.
src/windows/wslc/services/ImageService.cpp	Constructs warning adapter and passes it into image operations.
src/windows/wslc/services/ContainerService.h	Adds wslc.h include to support warning callback usage.
src/windows/wslc/services/ContainerService.cpp	Threads warning adapter into container create/start flows and implicit pull path.

[Copilot]

Pull request overview

Copilot reviewed 15 out of 15 changed files in this pull request and generated no new comments.