DTP: add another PDF export for summary tab

There should be only one PDF button still, but name and export function change depending on the selected tab (summary or set up of items, third tab will be moved to DO page #102).

Start by locating the existing PDF button, its export handlers, and the tab-selection entry point. Confirm how the summary and item-setup tabs are identified; done means one PDF button changes its name and export behavior with the selected tab, while the third tab is excluded as noted in issue #102.

Written by the indexing model from the issue text.