Improve support of nuget commands with file-based apps

[jjonescz]

Resolves #49200.
Needs NuGet/NuGet.Client#7169.

[Copilot]

Pull request overview

Extends file-based app support to NuGet-related CLI flows by integrating a virtual project builder into NuGet XPlat execution, so dotnet package * and dotnet nuget why can operate on *.cs entrypoints and reflect package changes back into #:package directives.

Changes:

• Add an IVirtualProjectBuilder implementation for file-based apps and a reflector that syncs NuGet-edited PackageReference items back into #:package directives.
• Route dotnet package add/remove/list and dotnet nuget why through updated NuGet XPlat entrypoints, including in-proc execution when needed.
• Update tests and remove the obsolete DirectivesRemoved localized resource entry.

Reviewed changes

Copilot reviewed 35 out of 35 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
test/dotnet.Tests/CommandTests/Run/RunFileTests.cs	Adds coverage for creating a NuGet-compatible virtual project root element from a file-based app.
test/dotnet.Tests/CommandTests/Project/Convert/DotnetProjectConvertTests.cs	Updates call-site for new VirtualProjectBuilder.CreateProjectInstance out parameter.
test/dotnet.Tests/CommandTests/Package/Remove/GivenDotnetRemovePackage.cs	Updates expectations to NuGet-driven output for file-based package removal.
test/dotnet.Tests/CommandTests/Package/List/GivenDotnetListPackage.cs	Adds test for listing packages for a file-based app via dotnet list … package.
test/dotnet.Tests/CommandTests/NuGet/GivenANuGetCommand.cs	Adds file-based app coverage for nuget why and package update.
src/Microsoft.DotNet.ProjectTools/VirtualProjectBuilder.cs	Extends CreateProjectInstance to also return a ProjectRootElement for reuse by NuGet.
src/Common/EnvironmentVariableNames.cs	Adds DOTNET_HOST_PATH constant.
src/Cli/dotnet/Parser.cs	Passes the virtual project builder into NuGet XPlat command registration.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.zh-Hant.xlf	Removes DirectivesRemoved translation entry.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.zh-Hans.xlf	Removes DirectivesRemoved translation entry.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.tr.xlf	Removes DirectivesRemoved translation entry.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.ru.xlf	Removes DirectivesRemoved translation entry.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.pt-BR.xlf	Removes DirectivesRemoved translation entry.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.pl.xlf	Removes DirectivesRemoved translation entry.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.ko.xlf	Removes DirectivesRemoved translation entry.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.ja.xlf	Removes DirectivesRemoved translation entry.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.it.xlf	Removes DirectivesRemoved translation entry.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.fr.xlf	Removes DirectivesRemoved translation entry.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.es.xlf	Removes DirectivesRemoved translation entry.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.de.xlf	Removes DirectivesRemoved translation entry.
src/Cli/dotnet/Commands/xlf/CliCommandStrings.cs.xlf	Removes DirectivesRemoved translation entry.
src/Cli/dotnet/Commands/Run/VirtualProjectBuildingCommand.cs	Adds NoConsoleLogger and tweaks restore/build target handling for virtual projects.
src/Cli/dotnet/Commands/Run/Api/RunApiCommand.cs	Updates call-site for new CreateProjectInstance out parameter ordering.
src/Cli/dotnet/Commands/Project/Convert/ProjectConvertCommand.cs	Updates call-site for new CreateProjectInstance out parameter.
src/Cli/dotnet/Commands/Package/VirtualProjectPackageReflector.cs	New: reflects NuGet PackageReference changes back into #:package directives.
src/Cli/dotnet/Commands/Package/Remove/PackageRemoveCommand.cs	Routes file-based removal through NuGet virtual project path instead of manual directive editing.
src/Cli/dotnet/Commands/Package/List/PackageListCommand.cs	Enables restore+list for file-based apps by using virtual project restore and NuGet runner selection.
src/Cli/dotnet/Commands/Package/Add/PackageAddCommand.cs	Routes file-based add through NuGet runner and uses virtual project build to generate restore graph when needed.
src/Cli/dotnet/Commands/NuGet/NuGetVirtualProjectBuilder.cs	New: implements NuGet XPlat IVirtualProjectBuilder for file-based apps.
src/Cli/dotnet/Commands/NuGet/NuGetCommand.cs	Adds in-proc NuGet runner selection for file-based scenarios and ensures DOTNET_HOST_PATH is set.
src/Cli/dotnet/Commands/CliCommandStrings.resx	Removes DirectivesRemoved resource.
src/Cli/Microsoft.DotNet.Cli.Definitions/Commands/Package/PackageListCommandDefinition.cs	Adds --file/--project options to dotnet package list and aligns path parsing API.
src/Cli/Microsoft.DotNet.Cli.Definitions/Commands/Hidden/List/ListReferenceCommandDefinition.cs	Updates hidden dotnet list to accept file paths via unified argument.
src/Cli/Microsoft.DotNet.Cli.Definitions/Commands/Hidden/List/ListPackageCommandDefinition.cs	Updates hidden dotnet list … package to accept file paths via unified argument.
src/Cli/Microsoft.DotNet.Cli.Definitions/Commands/Hidden/List/ListCommandDefinition.cs	Renames argument to “solution/project/file” to reflect new supported inputs.

[nkolev92]

Looks fine to me, nothing stands out.

Please get an SDK reviewer here, don't just rely on my approval.

[jjonescz]

@333fred @RikkiGibson @MiYanni for reviews, thanks

[RikkiGibson]

LGTM with some minor questions/concerns.

[jjonescz]

@333fred for another review, thanks

[jjonescz]

@333fred for another review, thanks

[333fred]

Consider using named parameters for discards like this.

[jjonescz]

/ba-g unrelated test failures, same as in #53759