fix(startup): prevent main thread hangs and optimize resource loading

- run start_sh initialization via QTimer.singleShot with timeout
- add timeout protection to load_theme_fonts()
- load Steam/EGS/PortProton games in parallel instead of sequential
- delay game loading until UI is fully initialized
- fix callback chaining to avoid blocking operations
- add proper timeout + error handling for all Steam/EGS network requests
- add timeouts for flatpak subprocess calls
- improve file I/O error handling to avoid UI freeze
- optimize theme font loading:
  - delay font loading via QTimer.singleShot
  - load fonts in batches of 10
  - reduce font load timeout to 3s
  - remove fonts only when switching themes

Signed-off-by: Boris Yumankulov <boria138@altlinux.org>

portprotonqt/app.py

@@ -34,13 +34,12 @@ def main():
     os.environ["PROCESS_LOG"] = "1"
     os.environ["START_FROM_STEAM"] = "1"
 
+    # Get the PortProton start command
     start_sh = get_portproton_start_command()
 
     if start_sh is None:
         return
 
-    subprocess.run(start_sh + ["cli", "--initial"])
-
     app = QApplication(sys.argv)
     app.setWindowIcon(QIcon.fromTheme(__app_id__))
     app.setDesktopFileName(__app_id__)
@@ -144,6 +143,22 @@ def main():
         save_fullscreen_config(False)
         window.showNormal()
 
+    # Execute the initial PortProton command after the UI is set up
+    def run_initial_command():
+        nonlocal start_sh
+        if start_sh:
+            try:
+                subprocess.run(start_sh + ["cli", "--initial"], timeout=10)
+            except subprocess.TimeoutExpired:
+                logger.warning("Initial PortProton command timed out")
+            except Exception as e:
+                logger.error(f"Error running initial PortProton command: {e}")
+        else:
+            logger.warning("PortProton start command not available, skipping initial command")
+
+    # Run the initial command after the UI is displayed
+    QTimer.singleShot(100, run_initial_command)
+
     # --- Cleanup ---
     def cleanup_on_exit():
         try: