feat(pdf exporter): improved test coverage, hardened tests, and feature enhancements

CHANGELOG.md

@@ -36,6 +36,13 @@ All notable changes for each version of this project will be documented in this
     - Fixed remote pages changing position before their replacements arrive and redundant requests for an already loaded initial range. Changes to a positive `totalItemCount` refresh the list without rebinding data; a reduced total excludes out-of-range records before filtering and grouping.
     - Reduced selection-resolution work during change detection. Each combo resolves its selection once per check and validates cached primitive-key matches before reusing them. Missing or invalid matches share one fallback scan; object keys retain deep-equality matching. In-place changes that create an earlier duplicate of a cached key are not detected without rebinding data.
 
+### Behavioral Changes
+
+- `IgxPdfExporterService`
+    - Summary rows are now shaded like the header row of the exported table. A summary closes the rows above it the way the header opens them, so it no longer reads as one more record. As with the header background, the shading follows the `showTableBorders` option.
+    - The row dimension cells of an `IgxPivotGrid` export are shaded the same way: they head the record they sit on rather than holding one of its values.
+    - A row dimension value that repeats down consecutive records of an `IgxPivotGrid` export is now drawn once, in a single cell over all of them, the way the grid merges its own row headers. A value merges only under the same parent dimension, so the same date under two different cities still gets a cell each, and a cell that would reach past the bottom of a page is cut off there and opened again under the headers of the next one.
+
 ### Breaking Changes
 
 - `IgxButtonDirective`, `IgxIconButtonDirective`