heise: news-tip route and the .NET beat

### Problem

A news item is a different route from a specialist article. heise staff write it, so it needs a hook rather than a manuscript. heise Developer has covered a C# build tool before: "Cake wird Projekt der .NET Foundation".

The .NET beat has a specific author. Holger Schwichtenberg writes an active .NET blog hosted on heise and is running a "Neu in .NET 10.0" series. He is the most relevant contact for a .NET tooling story.

### Outcome

A decision on whether there is a news hook worth sending, and if so, it is sent.

### Acceptance criteria

- [ ] Decide whether any upcoming milestone is a genuine news hook. A first stable calendar-version release on nuget.org is a candidate. A star count is not.
- [ ] If yes, submit through https://heise.de/tipps or the contact form at https://www.heise.de/kontakt/.

### Notes

Do not run this at the same time as #606, the specialist article, without checking the exclusivity rule in #605 first.

Part of #605.

Start by reading #605 and #606, then check the exclusivity rule before doing parallel outreach. Review upcoming milestones on nuget.org and decide whether a first stable calendar-version release is a genuine news hook; if so, submit through the heise tips or contact form. Done means the decision is recorded and any qualifying tip is sent.

Written by the indexing model from the issue text.