Open app in native view on starting it in GUI mode instead of on web browser

- Opens settings page on first run and landing page after in GUI mode
  Previously was only opening the GUI on linux after first run as it
  doesn't have a system tray
- Both the views are from the web interface but are rendered within
  the app instead of the browser

src/khoj/main.py

@@ -12,7 +12,6 @@ import logging
 import threading
 import warnings
 from platform import system
-import webbrowser
 
 # Ignore non-actionable warnings
 warnings.filterwarnings("ignore", message=r"snapshot_download.py has been made private", category=FutureWarning)
@@ -100,15 +99,10 @@ def run():
         server = ServerThread(start_server_func=lambda: start_server(app, host=args.host, port=args.port))
 
         logger.info(f"🌗 Khoj is running at {url}")
-        try:
-            startup_url = url if args.config else f"{url}/config"
-            webbrowser.open(startup_url)
-        except:
-            logger.warning(f"🚧 Unable to open browser. Please open {url} manually to configure or use Khoj.")
 
-        # Show Main Window on First Run Experience or if on Linux
-        if args.config is None or system() not in ["Windows", "Darwin"]:
-            main_window.show()
+        # Show config window on first run and main window otherwise
+        startup_window = main_window.show_page() if args.config else main_window.show_page("config")
+        startup_window()
 
         # Setup Signal Handlers
         signal.signal(signal.SIGINT, sigint_handler)