fix: add rel.DESCUENTO to all SQL queries; update debug endpoint with discount check

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

app/routes/debug_fb.py

@@ -63,5 +63,16 @@ async def find_cups(request: Request, user: dict = Depends(get_current_user)):
         results["muestra_articulo"] = rows5[0] if (ok5 and rows5) else "sin datos"
         results["cod_examen_muestra"] = cod
 
+    # 5. Verificar si hay descuentos en RELACION
+    ok6, _, rows6 = fb.execute_query("""
+        SELECT FIRST 10
+            r.NUM_FACTURA, r.PREFIJO, rel.COD_EXAMEN, rel.DESCUENTO, rel.PRECIO
+        FROM RELACION rel
+        JOIN RECEPCION r ON r.IDRECEPCION = rel.IDRECEPCION
+        WHERE rel.DESCUENTO IS NOT NULL AND rel.DESCUENTO > 0
+        ORDER BY r.FECHA_RECEPCION DESC
+    """)
+    results["servicios_con_descuento"] = rows6 if ok6 else []
+
     fb.disconnect()
     return JSONResponse(results)