Refactor OpenAPI client script and backend server logic.

Simplify and streamline OpenAPI client generation and backend startup logic. Improved error handling, environment configuration, and self-signed SSL certificate management. Added support for generating OpenAPI schema via command-line argument.

backend/main.py

@@ -167,13 +167,18 @@ if __name__ == "__main__":
         )
 
     # Run in CI mode
-    if is_ci:
+    if is_ci:  # CI mode
         print("CI mode detected: Starting server in a subprocess...")
+        # Ensure SSL certificate and key exist
+        if not Path(cert_path).exists() or not Path(key_path).exists():
+            print("Generating SSL certificates for CI mode...")
+            ssl_heidi.generate_self_signed_cert(cert_path, key_path)
+
         server_process = Process(target=run_server)
         server_process.start()
-        sleep(5)
-        server_process.terminate()
-        server_process.join()
+        sleep(5)  # Wait 5 seconds to ensure the server starts without errors
+        server_process.terminate()  # Terminate the server (test purposes)
+        server_process.join()  # Ensure proper cleanup
         print("CI: Server started and terminated successfully for test validation.")
     else:
         run_server()