Skip _ResolveBlazorWasmOutputs for .NET 11+ and move BlazorRoutingEnableRegexConstraint to SDK

[javiercn]

Summary

Updates the Blazor WebAssembly SDK to:

1. Skip the legacy _ResolveBlazorWasmOutputs target for .NET 11+ (framework assets handle blazor.webassembly.js)
2. Own the BlazorRoutingEnableRegexConstraint feature (moved from the package props file)

Changes

Microsoft.NET.Sdk.BlazorWebAssembly.Current.props

• Added BlazorRoutingEnableRegexConstraint property default (false) — previously shipped in the Microsoft.AspNetCore.Components.WebAssembly package props

Microsoft.NET.Sdk.BlazorWebAssembly.6_0.targets

• Added _TargetingNET110OrLater version check property
• Conditioned _ResolveBlazorWasmOutputs with Condition="'$(_TargetingNET110OrLater)' != 'true'" so it only runs for .NET 10 and earlier
• Added RuntimeHostConfigurationOption item for Microsoft.AspNetCore.Components.Routing.RegexConstraintSupport — flows the BlazorRoutingEnableRegexConstraint value to runtimeconfig.json configProperties, which the Mono WASM runtime reads and applies as an AppContext switch

How it works

For .NET 11+: The Microsoft.AspNetCore.Components.WebAssembly package now uses the SWA Framework Assets system. blazor.webassembly.js is declared with SourceType=Framework in the package props and automatically materialized by UpdateExistingPackageStaticWebAssets. No custom detection via BlazorWebAssemblyJSPath is needed.

For .NET 10 and earlier: _ResolveBlazorWasmOutputs continues to run as before, reading BlazorWebAssemblyJSPath from the package props file for backward compatibility.

Regex constraint support: The RuntimeHostConfigurationOption flows BlazorRoutingEnableRegexConstraint to runtimeconfig.json. The Mono WASM runtime reads configProperties and passes them to mono_wasm_load_runtime as AppContext key-value pairs, so AppContext.TryGetSwitch() works natively. The old AssemblyMetadataAttribute workaround in the aspnetcore repo has been removed.

Companion PR

• aspnetcore: Switch Blazor WebAssembly package to SWA Framework Assets and clean up custom props aspnetcore#65984

Testing

• .NET 11 Blazor WASM app: builds and runs with framework assets (no _ResolveBlazorWasmOutputs)
• .NET 10 Blazor WASM app: builds with backward-compatible BlazorWebAssemblyJSPath flow

[dotnet-policy-service]

Thanks for your PR, @@javiercn.
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[Copilot]

Pull request overview

This PR updates the Blazor WebAssembly SDK targets to stop running the legacy _ResolveBlazorWasmOutputs target for .NET 11+ builds, relying instead on Static Web Assets “Framework” assets to provide blazor.webassembly.js.

Changes:

• Added an MSBuild property _TargetingNET110OrLater based on TargetFrameworkVersion.
• Added a condition to _ResolveBlazorWasmOutputs so it only runs for .NET 10 and earlier (per the PR intent).
• Added explanatory comments describing the new behavior split.