Add .NET 11 breaking change article: MVC compatibility options removed

[Copilot]

The CompatibilityVersion enum and related MVC compatibility APIs — obsolete since ASP.NET Core 6 and no-ops since 3.0 — were removed in dotnet/aspnetcore#67077. This documents the removal for .NET 11 Preview 7.

New article

• aspnetcore/breaking-changes/11/mvc-compatibility-options-removed.md — covers version introduced, previous/new behavior, breaking change type (source + binary incompatible), reason, recommended action, and the affected APIs (SetCompatibilityVersion on both builder extension types, ConfigureCompatibilityOptions<TOptions>, MvcCompatibilityOptions, CompatibilityVersion).

Navigation

• aspnetcore/toc.yml — TOC entry under .NET 11 breaking changes.
• aspnetcore/breaking-changes/11/overview.md — table row, alphabetically placed, typed "Binary/source incompatible".

Related articles updated

• aspnetcore/mvc/compatibility-version.md — notes the .NET 11 removal in the 3.0+ moniker section and links to the new article.
• aspnetcore/mvc/overview.md — rewrites the "Compatibility version" section to past tense and links to the new article.

Recommended action documented is simply dropping the call:

// Before
services.AddMvc()
    .SetCompatibilityVersion(CompatibilityVersion.Latest);

// After
services.AddMvc();

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Internal previews

File	Preview link
aspnetcore/breaking-changes/11/mvc-compatibility-options-removed.md	aspnetcore/breaking-changes/11/mvc-compatibility-options-removed
aspnetcore/breaking-changes/11/overview.md	aspnetcore/breaking-changes/11/overview
aspnetcore/mvc/compatibility-version.md	aspnetcore/mvc/compatibility-version
aspnetcore/mvc/overview.md	aspnetcore/mvc/overview
aspnetcore/toc.yml	aspnetcore/toc