Shift-clicking a layer's name selected the layers from the last one
clicked to it, but Shift-clicking a layer bar in the time graph only
added that layer. Bars now select the same range (shared with the
name column: `shift_range`), and a click on a bar becomes where the next
range starts, as a click on a name does.
Test: timeline_shift_click_on_layer_bars_selects_the_range
(ui_workflow_selection).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Clicking an effect's name selected it (prop.select with the effect's group
uid) but group rows never painted the selection, so there was no feedback.
Group rows (effects, masks, shape groups...) now fill with row_selected when
selected, exactly like selected property rows.
Regression test: timeline_selected_effect_row_highlights.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
(cherry picked from commit 8b140428b39a24c3e1207ffde0430e759e316112)
