Only include System.Runtime.InteropServices.JavaScript in coreAssembly for Mono

[Copilot]

Fixes #122392

System.Runtime.InteropServices.JavaScript.dll is only required to start the Mono runtime on browser-wasm; CoreCLR does not need it to boot. It should therefore only be listed in the boot config's coreAssembly group when targeting Mono.

Changes

• BootJsonBuilderHelper: Added an IsMonoRuntime constructor flag. System.Private.CoreLib remains core for both runtimes; System.Runtime.InteropServices.JavaScript moved to a Mono-only core assembly list that is consulted only when IsMonoRuntime is set.
• GenerateWasmBootJson task: Added a UseMonoRuntime string parameter and computes the flag as !equals("false"), so unset/empty (the Mono default) preserves existing behavior and only UseMonoRuntime=false (CoreCLR) excludes the JS assembly.
• Microsoft.NET.Sdk.WebAssembly.Browser.targets: Passes UseMonoRuntime="$(UseMonoRuntime)" to both build and publish invocations and adds it to the incremental build/publish stamp content so the boot config regenerates when the runtime flavor changes.

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
12 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
12 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[Copilot]

Pull request overview

This PR adjusts WebAssembly boot config generation so System.Runtime.InteropServices.JavaScript.dll is only treated as a core boot-time assembly when targeting the Mono runtime, avoiding unnecessary inclusion for CoreCLR.

Changes:

• Adds a UseMonoRuntime task parameter and derives an isMonoRuntime flag in GenerateWasmBootJson.
• Extends BootJsonBuilderHelper with an IsMonoRuntime constructor flag and makes System.Runtime.InteropServices.JavaScript core-only for Mono.
• Plumbs $(UseMonoRuntime) through Microsoft.NET.Sdk.WebAssembly.Browser.targets and includes it in the incremental stamp content so boot config regenerates when the runtime flavor changes.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/GenerateWasmBootJson.cs	Adds UseMonoRuntime input and passes computed runtime-flavor flag into boot JSON building.
src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/BootJsonBuilderHelper.cs	Makes “core assembly” classification depend on runtime flavor, keeping JS interop core-only for Mono.
src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets	Passes UseMonoRuntime into GenerateWasmBootJson and adds it to build/publish stamp content for incrementality correctness.

[akoeplinger]

LGTM apart from one comment

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/BootJsonBuilderHelper.cs:22

• BootJsonBuilderHelper is a public type in the WebAssembly SDK tasks assembly. Changing the primary constructor signature is a source/binary breaking change for any external consumers that new up this helper directly. Consider adding a compat constructor overload with the previous signature that forwards to the new one (defaulting IsMonoRuntime to true to preserve prior behavior).

    public class BootJsonBuilderHelper(TaskLoggingHelper Log, string DebugLevel, bool IsMultiThreaded, bool IsPublish, Version TargetFrameworkVersion, bool IsMonoRuntime)
    {
#pragma warning disable SYSLIB1045 // Convert to 'GeneratedRegexAttribute'.
        internal static readonly Regex mergeWithPlaceholderRegex = new Regex(@"/\*!\s*dotnetBootConfig\s*\*/\s*{}");
        internal static readonly Regex bundlerFriendlyImportsRegex = new Regex(@"/\*!\s*bundlerFriendlyImports\s*\*/");