KiCad 10 changed `kicad-cli pcb export svg` in three ways that broke
get_board_2d_view (reported with a verified fix in #209):
- `--output` is now a FILE path, not a directory (a dir fails with
"Failed to create file '<dir>'").
- `--mode-single` is required to merge layers into one SVG (the default
multi-file behavior is deprecated).
- exit code 2 is returned for the deprecation warning even on success.
Pass a file path to `--output` and add `--mode-single` (both also valid on
KiCad 8/9). Stop gating on the exit code — judge success by whether an SVG was
actually produced — so the exit-2 deprecation warning is no longer a false
failure. Add regression tests for the exit-2-is-success case and the command
shape (file output + --mode-single).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>