API docs parity: .NET

## .NET API Docs

**Parent epic:** #1653

**Doc format:** [XML documentation comments](https://learn.microsoft.com/dotnet/csharp/language-reference/xmldoc/) (`/// `, ``, ``, etc.). The compiler emits a `.xml` file alongside the assembly.

**Culture:** **Strong and enforced.** NuGet packages conventionally include the XML doc file in the package (IDE IntelliSense reads it). Microsoft's own libraries always ship it. Roslyn analyzers can warn on missing docs.

**Hosting analogues:**

| Service | How it works |
|---------|-------------|
| ~~[fuget.org](https://www.fuget.org/)~~ | ⚠️ **Defunct** — DNS no longer resolves as of 2026-06-13. Was the closest analogue to javadoc.io for NuGet packages |
| [NuGet package page](https://www.nuget.org/) | Shows README, not full API surface |
| [DocFX](https://dotnet.github.io/docfx/) | Microsoft's Sphinx-equivalent generator; many projects self-host output on GitHub Pages |

> **Note on fuget.org:** fuget.org was the only third-party service that automatically rendered API docs from NuGet packages (analogous to javadoc.io). As of 2026-06-13 it is completely offline — DNS does not resolve. This means there is **no automatic, zero-config API docs host** for .NET packages. Self-hosted DocFX output (e.g. GitHub Pages from CI) is the only viable option.

**Key difference from Java:** The XML doc file ships *inside* the `.nupkg` (analogous to javadoc jar living in Maven Central), so IDEs can consume it without separate publication. But NuGet doesn't *mandate* it the way Maven Central does, and with fuget.org gone, there is no hosted equivalent to javadoc.io for .NET.