[release/11.0.1xx-preview1] Backport #52816

[lewing]

Backport of #52816 to release/11.0.1xx-preview1, based on @maraf's PR #52710.

Customer Issue

When multiple Blazor WASM client projects (e.g., FirstClient and SecondClient) are hosted by a single server project, users encounter a duplicate key error in FilterStaticWebAssetEndpoints. Both clients define the same HotReload JS module (Microsoft.DotNet.HotReload.WebAssembly.Browser.lib.module.js) as a static web asset with identical Identity values, causing the build to fail.

Additionally, the HotReload assembly version could be unpredictable when pulled from NuGet package sources, leading to potential version conflicts between the SDK and the referenced package.

Users cannot easily workaround these issues without modifying their project structure to use a single Blazor WASM client.

Description

This PR fixes both issues by embedding the HotReload functionality directly in the WebAssembly SDK:

1. Embeds HotReload in SDK: Replaces the PackageReference with content shipped inside the SDK, ensuring consistent versioning
2. Copy to intermediate folder: The HotReload JS module is copied to hotreload\ before being defined as a StaticWebAsset
3. Unique Identity: Each project now has a unique Identity for the asset (pointing to their own intermediate folder)
4. No filter changes needed: The copy-to-intermediate pattern naturally avoids duplicates without modifying filter logic

This follows the established pattern used by JSModules, ScopedCss, and ServiceWorker targets, and @javiercn's guidance: "What we do in other situations with assets like this is to copy them to the intermediate output folder before defining them."

Was this a regression?

• Yes
• No

Testing

The Publish_HostingMultipleBlazorWebApps_Works test now passes and validates the fix.

Risk

Low - this follows established patterns used elsewhere in the SDK for similar assets (JSModules, ScopedCss, ServiceWorker), and the change is well-tested. Embedding in the SDK also eliminates version conflicts.

[Copilot]

Pull request overview

Backport of changes that move the WebAssembly Hot Reload browser artifacts into the WebAssembly SDK layout (instead of an implicit package reference) and updates tests/baselines accordingly.

Changes:

• Update WebAssembly SDK MSBuild targets to source the Hot Reload JS module/DLL from the SDK layout and define it as a static web asset.
• Add packaging/build wiring to include the HotReloadAgent.WebAssembly.Browser outputs into the WebAssembly SDK layout.
• Refresh static web assets test baselines and normalize some test launchSettings values.

Reviewed changes

Copilot reviewed 27 out of 27 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
test/TestAssets/TestProjects/WatchBlazorWasmHosted/blazorhosted/Properties/launchSettings.json	Switch dotnetRunMessages from string to boolean for the test asset profile.
test/TestAssets/TestProjects/WatchBlazorWasm/Properties/launchSettings.json	Switch dotnetRunMessages from string to boolean for the test asset profile.
test/Microsoft.NET.Sdk.StaticWebAssets.Tests/StaticWebAssetsBaselineFactory.cs	Extend path templatization to recognize WebAssembly SDK paths.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/StaticWebAssets_Publish_Hosted_Works.Publish.files.json	Update expected publish file list baselines for new Hot Reload asset behavior.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/StaticWebAssets_Publish_DoesNotIncludeXmlDocumentationFiles_AsAssets.Publish.files.json	Update expected publish file list baselines for new Hot Reload asset behavior.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/StaticWebAssets_PublishMinimal_Works.Publish.staticwebassets.json	Update minimal publish static web assets baseline for new Hot Reload module placement/assets.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/StaticWebAssets_PublishMinimal_Works.Publish.files.json	Update minimal publish file list baseline.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/StaticWebAssets_Build_Hosted_Works.Build.staticwebassets.json	Update hosted build static web assets baseline for new Hot Reload module placement/assets.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/StaticWebAssets_BuildMinimal_Works.Build.staticwebassets.json	Update minimal build static web assets baseline for new Hot Reload module placement/assets.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/StaticWebAssets_BuildMinimal_Works.Build.files.json	Update minimal build file list baseline to include new Hot Reload outputs.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/Publish_DoesNotGenerateManifestJson_IncludesJSModulesOnBlazorBootJsonManifest.Publish.staticwebassets.json	Update publish baseline for JS-module/staticwebassets changes.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/Publish_DoesNotGenerateManifestJson_IncludesJSModulesOnBlazorBootJsonManifest.Publish.files.json	Update publish file list baseline.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/JsModules_Hosted_CanCustomizeBlazorInitialization.Publish.files.json	Update hosted JS modules publish file list baseline.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/JsModules_CanHaveDifferentBuildAndPublishModules.Publish.staticwebassets.json	Update publish static web assets baseline for JS module changes.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/JsModules_CanHaveDifferentBuildAndPublishModules.Publish.files.json	Update publish file list baseline for JS module changes.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/JsModules_CanCustomizeBlazorInitialization.Publish.staticwebassets.json	Update publish static web assets baseline for JS module changes.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/JsModules_CanCustomizeBlazorInitialization.Publish.files.json	Update publish file list baseline for JS module changes.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/JSModules_ManifestIncludesModuleTargetPaths.Build.staticwebassets.json	Update build static web assets baseline for JS module changes.
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/Build_DoesNotGenerateManifestJson_IncludesJSModulesOnBlazorBootJsonManifest.Build.staticwebassets.json	Update build baseline for JS-module/staticwebassets changes.
src/WasmSdk/Tasks/Microsoft.NET.Sdk.WebAssembly.Tasks.csproj	Add project reference + package layout inclusion for HotReloadAgent.WebAssembly.Browser outputs into the WebAssembly SDK.
src/WasmSdk/Sdk/Sdk.targets	Add _WasmImplicitlyReferenceHotReload target to copy hot reload JS module to intermediates and define it as a static web asset.
src/BuiltInTools/HotReloadAgent.WebAssembly.Browser/Microsoft.DotNet.HotReload.WebAssembly.Browser.csproj	Adjust the HotReload browser agent project to build as a non-Razor SDK project and include wwwroot content in outputs.
build/RunTestsOnHelix.sh	Remove adding %DOTNET_ROOT%/.nuget as a NuGet source (now only Testpackages is added).
build/RunTestsOnHelix.cmd	Remove adding %DOTNET_ROOT%\\.nuget as a NuGet source (now only Testpackages is added).