feat: add use_cropbox parameter to align rasterizer APIs

Added use_cropbox parameter to rasterize_pdf_page hook to allow
choosing between MediaBox and CropBox rendering:

- Default is use_cropbox=False (MediaBox) for consistency with
  Ghostscript's existing behavior
- Ghostscript: passes -dUseCropBox when use_cropbox=True
- pypdfium: calculates crop values to expand from CropBox to MediaBox
  when use_cropbox=False

This aligns both rasterizers to produce the same output dimensions
by default, making the rasterizer choice transparent for page
geometry.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/plugins/gs_raster_failure.py

@@ -29,6 +29,7 @@ def rasterize_pdf_page(
     filter_vector,
     stop_on_soft_error,
     options,
+    use_cropbox,
 ) -> Path:
     with patch('ocrmypdf._exec.ghostscript.run') as mock:
         mock.side_effect = raise_gs_fail
@@ -43,6 +44,7 @@ def rasterize_pdf_page(
             filter_vector=filter_vector,
             stop_on_soft_error=stop_on_soft_error,
             options=options,
+            use_cropbox=use_cropbox,
         )
         mock.assert_called()
         return output_file

tests/plugins/gs_raster_soft_error.py

@@ -30,6 +30,7 @@ def rasterize_pdf_page(
     filter_vector,
     stop_on_soft_error,
     options,
+    use_cropbox,
 ) -> Path:
     with patch('ocrmypdf._exec.ghostscript.run') as mock:
         mock.side_effect = fail_if_stoponerror
@@ -44,6 +45,7 @@ def rasterize_pdf_page(
             filter_vector=filter_vector,
             stop_on_soft_error=stop_on_soft_error,
             options=options,
+            use_cropbox=use_cropbox,
         )
         mock.assert_called()
         return output_file