Reshape BrowserConfiguration API per review (BrowserOptions) while preserving the JS wire format

[Copilot]

API-review feedback on the server-to-client Blazor browser configuration (#66393): rename/reshape the public surface to match ASP.NET Core options conventions, while keeping the serialized <!--Blazor-Configuration:...--> payload aligned with the existing Web.JS consumer.

Description

• Root model: BrowserConfiguration → BrowserOptions. LogLevel is now Microsoft.Extensions.Logging.LogLevel? (JS enum values are identical, 0–6). Server/Ssr/WebAssembly are get-only and pre-initialized to avoid NREs on the common path.
• InteractiveServerBrowserOptions (was ServerBrowserOptions): ReconnectionRetryIntervalMilliseconds (int?) → ReconnectionRetryInterval (TimeSpan?).
• SsrBrowserOptions: CircuitInactivityTimeoutMs → CircuitInactivityTimeout (TimeSpan?); DisableDomPreservation → positive PreserveDom (bool?).
• WebAssemblyBrowserOptions: EnvironmentVariables is now a get-only, non-null IDictionary<string, string>.
• ConfigureBrowser: Configuration parameter → Options.
• Assembly placement: BrowserOptions and the InteractiveServerBrowserOptions/SsrBrowserOptions/WebAssemblyBrowserOptions types now live in Microsoft.AspNetCore.Components.Endpoints (the public namespace stays Microsoft.AspNetCore.Components), alongside the related ConfigureBrowser component and helpers, since they are written by the ASP.NET Core host during SSR and only read by JS.
• HttpContext accessor: BrowserConfigurationHttpContextExtensions.GetBrowserConfiguration → BrowserOptionsHttpContextExtensions.GetBrowserOptions.
• Endpoint builder: WithBrowserConfiguration → WithBrowserOptions (configureOptions).
• Wire format: instead of a separate wire model, BrowserOptions is serialized directly with [JsonPropertyName] plus small internal JsonConverters that adapt the idiomatic C# shapes to the JS-expected JSON (TimeSpan → milliseconds, positive PreserveDom → disableDomPreservation, LogLevel → int). JS remains the source of truth and is kept in sync with the .NET bits. No TypeScript changes required.
• Updated PublicAPI.Unshipped.txt for both assemblies and the E2E test-asset startup.

All types are sealed (as they already were). ConfigureBrowser retains [Parameter, EditorRequired] on Options and [CascadingParameter] on HttpContext.

app.MapRazorComponents<App>()
    .WithBrowserOptions(options =>
    {
        options.LogLevel = LogLevel.Warning;
        options.Server.ReconnectionMaxRetries = 10;
        options.Server.ReconnectionRetryInterval = TimeSpan.FromSeconds(1.5);
        options.Ssr.PreserveDom = true;
        options.WebAssembly.EnvironmentVariables["OTEL_ENDPOINT"] = "https://...";
    });

[javiercn]

@copilot here is some feedback for you to address

[javiercn]

Looks good to me. @copilot update the original api review issue so the description reflects the new api shape.

[Copilot]

Pull request overview

Reshapes the Blazor server-to-browser configuration surface to follow ASP.NET Core “options” conventions (renaming BrowserConfiguration → BrowserOptions, adjusting option types), while keeping the serialized <!--Blazor-Configuration:...--> payload compatible with the existing JS consumer.

Changes:

• Renames/reshapes the public API surface (WithBrowserConfiguration → WithBrowserOptions, GetBrowserConfiguration → GetBrowserOptions, ConfigureBrowser.Configuration → .Options) and updates option types (TimeSpan?, LogLevel?, positive PreserveDom).
• Serializes BrowserOptions directly using source-generated JsonSerializerContext plus internal converters to preserve the existing JS wire format.
• Moves/removes the old public types from Components and introduces the new public types in Components.Endpoints (public namespace remains Microsoft.AspNetCore.Components).

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/Components/test/testassets/Components.TestServer/RazorComponentEndpointsStartup.cs	Updates test-asset endpoint setup to use WithBrowserOptions.
src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Streaming.cs	Switches runtime emission to GetBrowserOptions() and BrowserOptionsJsonContext.
src/Components/Endpoints/src/Rendering/BrowserOptionsJsonContext.cs	Renames/moves the source-gen JSON context to target BrowserOptions.
src/Components/Endpoints/src/PublicAPI.Unshipped.txt	Updates public API tracking for the new/moved types and members.
src/Components/Endpoints/src/Builder/RazorComponentsEndpointConventionBuilderExtensions.cs	Renames endpoint builder API to WithBrowserOptions(...).
src/Components/Endpoints/src/BrowserConfiguration/WebAssemblyBrowserOptions.cs	Makes EnvironmentVariables get-only/non-null and changes type to IDictionary<,>.
src/Components/Endpoints/src/BrowserConfiguration/SsrBrowserOptions.cs	Introduces SSR options with converters for JS wire compatibility (PreserveDom, TimeSpan).
src/Components/Endpoints/src/BrowserConfiguration/InteractiveServerBrowserOptions.cs	Renames server options type and switches retry interval to TimeSpan? with ms converter.
src/Components/Endpoints/src/BrowserConfiguration/ConfigureBrowser.cs	Renames parameter to Options and updates merge behavior for new shapes.
src/Components/Endpoints/src/BrowserConfiguration/BrowserOptionsJsonConverters.cs	Adds internal converters to adapt idiomatic C# shapes to the existing JS payload format.
src/Components/Endpoints/src/BrowserConfiguration/BrowserOptionsHttpContextExtensions.cs	Renames HttpContext accessor to GetBrowserOptions().
src/Components/Endpoints/src/BrowserConfiguration/BrowserOptions.cs	Adds the new root options model with get-only nested option objects.
src/Components/Components/src/PublicAPI.Unshipped.txt	Removes the old API entries from the Components assembly public API tracking.
src/Components/Components/src/BrowserConfiguration/SsrBrowserOptions.cs	Removes old SSR options shape from Components.
src/Components/Components/src/BrowserConfiguration/BrowserConfiguration.cs	Removes old root configuration model from Components.

Comments suppressed due to low confidence (2)

src/Components/Endpoints/src/Rendering/BrowserOptionsJsonContext.cs:12

• BrowserOptions is declared in Microsoft.AspNetCore.Components, but this file is in Microsoft.AspNetCore.Components.Endpoints and doesn’t import the parent namespace. As written, [JsonSerializable(typeof(BrowserOptions))] won’t compile because BrowserOptions can’t be resolved from this namespace.
  src/Components/Endpoints/src/BrowserConfiguration/BrowserOptionsHttpContextExtensions.cs:32
• GetBrowserOptions currently returns the BrowserOptions instance stored in endpoint metadata directly. Since BrowserOptions (and its nested options/dictionaries) are mutable and callers/components merge into it per request, this can cause cross-request state leakage and concurrency issues. Clone into a per-request instance before storing it in HttpContext.Items.