"Microsoft.Windows.WinmdGenerator" fails from msbuild

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With a basic `.proj` file:

```xml

net8.0
$(OutputPath)\Microsoft.Windows.Component.winmd
1.0.0.0
false

```

It does some amount of processing with a 'dotnet build':

```
> dotnet build
Determining projects to restore...
All projects are up-to-date for restore.
Microsoft.Windows.Component.Metadata ->
Scraping headers for crossarch...
Scraping constants and enums...
Writing winmd...
Winmd emitted at: \Microsoft.Windows.Component.winmd

Build succeeded.
0 Warning(s)
0 Error(s)
```

But with "msbuild" it fails:

```
> msbuild
MSBuild version 17.14.23+b0019275e for .NET Framework
Build started 11/11/2025 10:15:55 AM.

Project "Q:\source\WinMdGenerationRepro\Metadata\Microsoft.Windows.Component.Metadata\Microsoft.Windows.Component.Metadata.csproj" on node 1 (default targets).
CoreGenerateAssemblyInfo:
Skipping target "CoreGenerateAssemblyInfo" because all output files are up-to-date with respect to the input files.
_GenerateSourceLinkFile:
Source Link is empty, file 'obj\Debug\net8.0\Microsoft.Windows.Component.Metadata.sourcelink.json' does not exist.
CopyFilesToOutputDirectory:
Microsoft.Windows.Component.Metadata ->
C:\.tools\.nuget\packages\microsoft.windows.winmdgenerator\0.67.4-preview\Sdk\Sdk.targets(101,5): error MSB4062: The "MetadataTasks.PrepSettingsForFunctionPointerFixups" task could not be loaded
from the assembly C:\.tools\.nuget\packages\microsoft.windows.winmdgenerator\0.67.4-preview\tools\net8.0\MetadataTasks.dll. Could not load file or assembly 'System.Runtime, Version=8.0.0.0, Cultu
re=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified. Confirm that the declaration is correct, that the assembly and all
its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask. [Q:\source\WinMdGenerationRepro\Metadata\Microsoft.Windows.Component.Met
adata\Microsoft.Windows.Component.Metadata.csproj]
Done Building Project "Q:\source\WinMdGenerationRepro\Metadata\Microsoft.Windows.Component.Metadata\Microsoft.Windows.Component.Metadata.csproj" (default targets) -- FAILED.

Build FAILED.

"Q:\source\WinMdGenerationRepro\Metadata\Microsoft.Windows.Component.Metadata\Microsoft.Windows.Component.Metadata.csproj" (default target) (1) ->
(PrepSettingsForFunctionPointerFixups target) ->
C:\.tools\.nuget\packages\microsoft.windows.winmdgenerator\0.67.4-preview\Sdk\Sdk.targets(101,5): error MSB4062: The "MetadataTasks.PrepSettingsForFunctionPointerFixups" task could not be loade
d from the assembly C:\.tools\.nuget\packages\microsoft.windows.winmdgenerator\0.67.4-preview\tools\net8.0\MetadataTasks.dll. Could not load file or assembly 'System.Runtime, Version=8.0.0.0, Cul
ture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified. Confirm that the declaration is correct, that the assembly and al
l its dependencies are available, and that the task contains a public class that implements Microsoft.Build.Framework.ITask. [Q:\source\WinMdGenerationRepro\Metadata\Microsoft.Windows.Component.M
etadata\Microsoft.Windows.Component.Metadata.csproj]

0 Warning(s)
1 Error(s)

Time Elapsed 00:00:02.40
```

Reproduce the failure with the basic .proj file using both dotnet build and msbuild. Inspect Sdk/Sdk.targets at line 101 and the tools/net8.0/MetadataTasks.dll task-loading path; done when the Microsoft.Windows.WinmdGenerator project builds successfully with msbuild as well as dotnet build.

Written by the indexing model from the issue text.