Tighten assembly-tree row height to 22px

Default DataGridRow height from the Simple theme is ~28px — visibly
looser than the SearchPane ListBox rows (which sit at ~22px with the
icon+text template). Pin TreeGrid RowHeight to 22 so the two panes
match: 16px icon + 3px top + 3px bottom.

Assisted-by: Claude:claude-opus-4-7:Claude Code

ILSpy/AssemblyTree/AssemblyListPane.axaml

@@ -25,6 +25,7 @@
 	          HierarchicalRowsEnabled="True"
 	          GridLinesVisibility="None"
 	          CanUserResizeColumns="False"
+	          RowHeight="22"
 	          SelectionMode="Extended"
 	          SelectionChanged="OnTreeGridSelectionChanged">
 		<DataGrid.Columns>