Migrate fullscreen overlay selectors onto routeSgrMouseInput() and
routeSelectListMouse(), removing duplicated SGR parsing and SelectList
hit-test boilerplate. Behavior-preserving: wheel step sizes, footer/row
offset guards, and consumption semantics are unchanged.
Make the inline-picker wrappers (theme/thinking/queue-mode/show-images/
plugin) MouseRoutable, each subtracting their single top-border row before
delegating to SelectList.routeMouse(). Name previously magic coordinate
offsets (spacerRowsAfterTabs, contentColInset).
When a plugin is installed in both user and project scope, the selector
now shows separate scoped entries (e.g. 'plugin-name@1.0 [project]' and
'plugin-name@1.0 [user]') and forwards the selected scope to
uninstallPlugin(), preventing the disambiguation error introduced when
dual-scope support was added.
can1357