Small UI polish: dialog dismiss guards, tooltips and copy-link buttons

Rescan/split and duplicate-compare dialogs can no longer be closed by Escape or an outside click mid-save; the waste list shows full generator and P.I. names on hover; an empty compound-class tile ends in a period like its siblings; equipment's photo strip loads lazily; and the chemical and chemical-group detail pages got the copy-link button every other detail page already has.