Webapp-Icons: Content-Type auch fuer Vorlagen-Icons nachschlagen

get_webapp_icon kannte nur workspace_webapps/gruppen_webapps, Icons von
webapp_templates kamen als application/octet-stream.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app.py

@@ -5090,11 +5090,15 @@ def get_webapp_icon(filename: str):
                 SELECT icon_content_type FROM workspace_webapps WHERE icon_filename = %s
                 UNION ALL
                 SELECT icon_content_type FROM gruppen_webapps WHERE icon_filename = %s
+                UNION ALL
+                SELECT icon_content_type FROM webapp_templates WHERE icon_filename = %s
                 LIMIT 1
                 """,
-                (safe_name, safe_name),
+                (safe_name, safe_name, safe_name),
             )
             row = cur.fetchone()
+    # Vorlagen-Icons fehlten hier bis 09.10.2026 und kamen als
+    # application/octet-stream.
     media_type = row[0] if row and row[0] else "application/octet-stream"
 
     return FileResponse(file_path, media_type=media_type)