debug: /api/sftp-test returns JSON on connect failure

backend/api.py

@@ -241,7 +241,10 @@ def api_sftp_test():
 
     t0 = time.time()
     # HARD socket timeout
-    sock = socket.create_connection((host, port), timeout=timeout)
+    try:
+        sock = socket.create_connection((host, port), timeout=timeout)
+    except Exception as e:
+        return JSONResponse({"ok": False, "stage": "connect", "error": str(e), "host": host, "port": port, "timeout": timeout}, status_code=502)
     t_sock = time.time()
 
     tr = paramiko.Transport(sock)