Update Moq to 4.21.0

[ekwav-agent]

Summary

Behaviour: Nothing changes for users. The test build now uses Moq 4.21.0 instead of 4.20.72. Moq is only referenced in non-Release configurations, so the production build is unaffected.

Change: In SkyModCommands.csproj, the Moq PackageReference goes from 4.20.72 to 4.21.0. The repository has no NuGet lockfile, so nothing else needed updating.

Test: No new test, since this is a version bump. I rebuilt the Dockerfile's layout (sibling repos cloned next to sky/) and ran dotnet test there. All 331 of 331 existing tests passed, including every test that uses Moq, and restore resolved Moq/4.21.0.

Open: Upgrading Moq also raises its transitive dependency Castle.Core. The resolved version is now 5.2.1, up from the 5.1.1 minimum that 4.20.72 allowed, because 4.21.0 requires at least 5.2.1.

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Dependency notes:

• Moq 4.21.0 is the upgrade this task asked for. It comes from nuget.org and was published 2026-09-24, which is more than a day ago.
• The package lists no known vulnerabilities, and its source repository is github.com/moq/moq.
• The package only contains lib/* assemblies, with no build/ or analyzers/ content.
• The sibling repo SkyFilter still references Moq 4.20.72. That doesn't cause a conflict, because NuGet picks the higher version (4.21.0).

Where to look: 0 changed lines of production code in 0 files, 0 changed lines of tests in 0 files, 1 other file.

Validation: 1/1 checks passed · reviewed in a separate codex session.

Dependencies: 3 changed, verified by the host.

Package	Change	Released	Accepted by	Advisories
nuget:Moq	4.20.72 → 4.21.0	2026-09-24	age (3 days)	none
nuget:Castle.Core	added 5.2.1	2025-03-09	age (567 days)	none
nuget:System.Threading.Tasks.Extensions	added 4.6.3	2025-04-04	age (541 days)	none

Checks and provenance

• container_build

Review notes:

• Round 1: The reported 331 passing tests could not be independently verified because test artifacts were unavailable; the required host Docker build runs the existing suite before publication.

Task: task_c6vuvmnd7eoh3v7c3ciq

Base: main at 7bce2f2f4e793a022346e802d7265a0ec24f39de