Golem beta forum: post about Fallout

### Problem

Chris is in the beta programme for Golem's new forum and social platform. A short post there is the cheapest outreach available: no editor, no exclusivity rule, no German article to write first.

### Outcome

A short introductory post about Fallout is published on the platform.

### Acceptance criteria

- [ ] Check the platform's rules on self-promotion before posting. A beta community can be strict about it.
- [ ] Post written in German, framed as "a fork of NUKE now carries the project" rather than as an advertisement.
- [ ] Link recorded here.

### Notes

Do this before the press pitches. It costs almost nothing and any replies are useful signal on which framing lands.

Independent of the exclusivity rule in #605, which covers articles and not forum posts. Worth confirming that assumption if the platform has an editorial link to the newsroom.

Part of #605.