Clarify MSBuild NuGet onboarding

[ntoskrnl7]

Summary

• Add first-screen README and Korean README guidance for MSBuild/NuGet package consumption.
• Document both PackageReference and Install-Package crtsys, including Build Tools-only msbuild /restore usage.
• Add dedicated English/Korean MSBuild/NuGet quick-start docs and link them from architecture docs.
• Connect the public NuGet onboarding docs to the checked-in test/nuget consumer smoke projects.
• Make the NuGet package README self-contained for nuget.org and remove package-page documentation links that could resolve poorly there.
• Harden the CPM bootstrap wrapper so CI creates the download directory, validates cached/downloaded CPM contents, re-downloads invalid cached files, checks file(DOWNLOAD) status, and fails clearly if CPMAddPackage is not defined.
• Extend x86 driver coverage across CMake CI, NuGet prebuilt libraries, NuGet driver consumer tests, and prebuilt release asset smoke tests.

Impact

This makes it clear that crtsys NuGet consumption works for Visual Studio and Build Tools-only WDK driver projects. It also separates MSBuild/NuGet onboarding from the CMake/CPM/prebuilt paths so readers do not mistake multiple supported paths for extra setup burden.

The package README now carries the package-page quick start directly instead of relying on repository-relative documentation links.

The CPM bootstrap change addresses the app configure failure where the wrapper printed a CPM download message but proceeded to CPMAddPackage without proving that the downloaded CPM script was valid. It now self-heals an invalid cached CPM file by deleting and downloading it again before including it.

The x86 change aligns crtsys with the existing script/toolchain capability: x86 driver builds now run in CI and x86 prebuilt driver libraries are packaged alongside x64 and ARM64. Runtime x86 driver load tests still require a 32-bit Windows test machine and remain separate from GitHub-hosted compile/package validation.

Validation

• git diff --check
• XML parse check for test/nuget/crtsys_nuget_test.vcxproj, nuget/build/native/crtsys.targets, and nuget/build/native/crtsys.props
• Verified local WDK km library folders exist for x86, x64, and ARM64 under 10.0.22621.0
• Verified nuget/README.md has no Markdown documentation links or repository-relative links.

Local cmake is not available in this shell, so the GitHub Actions jobs should be used to verify the CPM bootstrap and x86 driver/package build expansion.