ICS import: select all past events at once (range-select and/or a button)

[hhkaos]

When importing events from an .ics file, picking which upcoming events to bring in is one click per event. For a feed with a long history, marking every past event (e.g. to exclude them, or to bulk-handle them differently from upcoming ones) means clicking each one individually.

Requested:

• Range-select: click one, then Shift/Alt-click another, selects everything in between (standard list multi-select pattern).
• And/or a dedicated button — "select all past" — given "past vs. upcoming" is a very common split for this exact list.