zbx_dc_item_t.timeout is set when preparing item before polling (zbx_prepare_items) with following steps:

1. copy from timeout_origin
2. expand macros
3. validate timeout

The timeout validation step can optionally return converted timeout in seconds. It would make things more simple if the converted timeout would be stored in zbx_dc_item_t as integer rather than in string format.

This change would affect item polling (server/proxy side) and network discovery. This does not affect active agent handling and proxy-server configuration sync.