fix(rdesign): remove --no-gui flag so Scribus runner script executes

Scribus 1.5 --no-gui mode doesn't execute --python-script properly.
Remove the flag and let Scribus use the Xvfb display, which also
enables the runner to create the bridge socket.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker/scribus-novnc/bridge/server.py

@@ -110,8 +110,9 @@ def start_scribus():
     env = os.environ.copy()
     env["DISPLAY"] = DISPLAY
 
+    env["XDG_RUNTIME_DIR"] = "/tmp/runtime-root"
     _scribus_proc = subprocess.Popen(
-        ["scribus", "--python-script", SCRIBUS_RUNNER, "--no-gui"],
+        ["scribus", "--python-script", SCRIBUS_RUNNER],
         env=env,
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,