ci: PSGallery publish only on manual dispatch, not on tag push

The PowerShell Gallery is not kept current; distribution runs via GitHub Releases.
Switch the publish-psgallery workflow trigger to workflow_dispatch so tagging a
release no longer publishes to PSGallery. The publish-module (GitHub Release)
workflow still runs on tag push.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: Uwe Janke

.github/workflows/publish-psgallery.yml

@@ -18,10 +18,10 @@
 
 name: Publish to PowerShell Gallery
 
+# Bewusst NICHT automatisch bei Tag-Push - die PSGallery wird derzeit nicht aktuell
+# gehalten (Distribution laeuft ueber GitHub Releases). Nur manuell ausloesbar.
 on:
-  push:
-    tags:
-      - 'v*.*.*'
+  workflow_dispatch:
 
 permissions:
   contents: read