[browser][coreclr] Add --UseMonoRuntime parameter to wasmbrowser template (default: true)

[Copilot]

Description

Adds a --UseMonoRuntime boolean parameter to the wasmbrowser template that controls whether <UseMonoRuntime>false</UseMonoRuntime> is included in the generated project file when the parameter is set to false. Default is true.

Template changes:

• Added UseMonoRuntime symbol in template.json (boolean, default: true)
• Added conditional property in browser.0.csproj using template engine directives with inverted logic

Usage:

# Default behavior - no property emitted (Mono runtime used by default)
dotnet new wasmbrowser -n MyApp

# Explicitly disable Mono runtime
dotnet new wasmbrowser -n MyApp --UseMonoRuntime false

The logic is inverted so that <UseMonoRuntime>false</UseMonoRuntime> is only emitted when the parameter is explicitly set to false. When true (default), no property is emitted since Mono runtime is the default behavior for WebAssembly browser apps.

Testing:

• Added UseMonoRuntimeParameter test covering true/false/default cases
• Validates presence/absence of property in generated csproj with inverted logic

Contributes to dotnet/sdk#51240

Original prompt

Update the wasmbrowser template to add a --usemonoruntime parameter (default: true). When this parameter is set to true, add false to the generated project file. Ensure the template help text and documentation are updated, and add or update template tests to cover both parameter settings.

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[Copilot]

Pull request overview

This PR adds a new --UseMonoRuntime boolean parameter to the wasmbrowser dotnet template that controls whether the generated project explicitly opts out of the Mono runtime. The parameter defaults to true, and when set to false, the template emits <UseMonoRuntime>false</UseMonoRuntime> in the generated project file to enable CoreCLR for WebAssembly scenarios.

Key Changes:

• Added UseMonoRuntime template parameter with boolean type and true default value
• Implemented inverted conditional logic in project template to emit property only when parameter is false
• Added comprehensive test coverage for all parameter scenarios (true, false, and default)

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/mono/wasm/templates/templates/browser/.template.config/template.json	Adds the UseMonoRuntime boolean parameter definition with default value true and appropriate description
src/mono/wasm/templates/templates/browser/browser.0.csproj	Adds conditional template directive to emit <UseMonoRuntime>false</UseMonoRuntime> only when parameter is set to false
src/mono/wasm/Wasm.Build.Tests/Templates/WasmTemplateTests.cs	Adds test method UseMonoRuntimeParameter to verify correct behavior for all parameter values (true, false, default)