The Kotlin backend checked its documentation with Dokka; the ASP.NET Core
API had only the compiler warning for a public declaration without a
comment. CI now builds the API reference with DocFX, every warning as an
error, and Documents/api/CheckDocumentation.cs fails when a namespace,
type or member of the reference has no description, internal and
private members included. The setup is the one Progmaweb uses: the
docfx tool pinned in .config/dotnet-tools.json, the configuration and
the namespace description under Documents/api, and the generated
reference ignored.

The language website ran a Spring Boot application on JVM 25 for two
endpoints, and it was the only JVM on the server: a quarter of a
gigabyte of resident memory for /api/v1/site and /health. The server
already runs ASP.NET Core 10 for Progmaweb.

The API is now Progmasoft.Tala.Website.Api, a minimal ASP.NET Core 10
application under the namespace Progmasoft.Tala.Website. It answers as
before: /api/v1/site returns the site's own state as the same JSON,
POST is not allowed there, /health answers with an empty 200, and every
other path is 404. It listens on 127.0.0.1, port 5086 unless PORT says
otherwise, as the Spring process did, so Nginx is unchanged.

- Progmasoft.Tala.Website.slnx, Directory.Build.props and global.json
  set up the solution with warnings as errors, documentation comments
  required and NuGet lock files.
- Progmasoft.Tala.Website.Api.Tests runs the endpoints in an in-memory
  host with xUnit v3 on Microsoft.Testing.Platform.
- ops/systemd/tala-site-api.service runs the published DLL on the shared
  runtime from /srv/xsharp/website/current/site-api, with the hardening
  of the unit it replaces.
- CI builds, tests, publishes and reports coverage with dotnet; CodeQL
  analyzes C# instead of Kotlin; Renovate watches NuGet instead of
  Gradle.

Move the Progmasoft mail operations baseline to its owning Progmaweb repository, remove the retired Astro account UI and duplicate identity backend, keep only the ViGet health boundary, add canonical sitemap signals, strengthen dependency CI, and adopt Patent Grant 1.1 across project-owned files.