Fix web GUI WebSocket: use relative public_url

Setting public_url="" makes textual-serve generate relative
WebSocket URLs so the browser connects to the correct host
regardless of whether accessed via localhost or remote IP.

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

tui/__main__.py

@@ -12,12 +12,21 @@ def main():
     if "--web" in sys.argv:
         from textual_serve.server import Server
         port = 8080
+        host = "0.0.0.0"
         for i, arg in enumerate(sys.argv):
             if arg == "--port" and i + 1 < len(sys.argv):
                 port = int(sys.argv[i + 1])
+            elif arg == "--host" and i + 1 < len(sys.argv):
+                host = sys.argv[i + 1]
         os.environ["PYTHONPATH"] = f"{_ROOT}:{os.environ.get('PYTHONPATH', '')}"
         os.environ["GNIZA_DIR"] = _ROOT
-        server = Server("python3 -m tui", host="0.0.0.0", port=port, title="gniza")
+        server = Server(
+            "python3 -m tui",
+            host=host,
+            port=port,
+            title="gniza",
+            public_url="",
+        )
         server.serve()
     else:
         app = GnizaApp()