A module template, extracted from the tutorial so the two cannot drift

Extracted from the walkthrough in #729 once that exists, so the two cannot disagree.

A `BarakoCMS.Module.Template` that clones and builds: the csproj with the project reference and no
inline versions, the module class already registered, one lifecycle hook, one endpoint in the
vertical slice layout, and tests including the authorisation one.

Sequenced after the tutorial deliberately. A template written first teaches by example only, and
the questions a newcomer actually has ("why is there no version in the csproj", "where does the
hook get registered", "why does the test assert a 403") are answered by prose, not by a file that
already contains the answer.

Worth deciding: a repository with the GitHub template flag set, or `dotnet new` template packaged
on NuGet. The second is a better experience and more to maintain. The first is free.

## Done when

`git clone`, `dotnet test`, green. Then delete one file and the tutorial explains what it was for.

Start with the walkthrough in #729, then inspect the existing module csproj, module class, lifecycle hook, endpoint, and authorization tests that the template must represent. Resolve whether this should use the GitHub template flag or a NuGet-packaged dotnet new template. Done means a fresh clone passes dotnet test and deleting one generated file is explained by the tutorial.

Written by the indexing model from the issue text.