Users can now show/hide the Service Discovery / copy buttons column
from the view.py menu bar instead of always seeing it, with the choice
remembered across reloads and views.
Checkmk's native checkbox-list widget renders one row per item with no
grouping or pagination, making rules like "Deploy custom files with
agent" hard to work with when only a few items need to be checked
among hundreds. Adds a search box, a live selected-count, and a
"Selected only" toggle above any such list with 15+ items.
Hostnames longer than 32 characters are now truncated with an ellipsis
in view.py tables, with the full name shown as a tooltip on hover. The
copy buttons in the Extra column keep copying the full, untruncated
hostname regardless of the displayed text.
