test: add pytest.importorskip for cairosvg-dependent tests

Gracefully skips figment tests when system Cairo library is unavailable
instead of crashing with opaque OSError during test collection.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_figment_render.py

@@ -2,6 +2,10 @@
 
 import os
 
+import pytest
+
+pytest.importorskip("cairosvg", reason="cairosvg requires system Cairo library")
+
 from engine.figment_render import rasterize_svg
 
 FIXTURE_SVG = os.path.join(os.path.dirname(__file__), "fixtures", "test.svg")