test(render): add P2 GPU visibility acceptance and benchmark harness

cmake/GpuVisibilityAcceptance.cmake

@@ -0,0 +1,13 @@
+# P2's image-equivalence tests use the real offscreen Vulkan renderer. Keep the benchmark
+# executable available without making performance thresholds part of CTest.
+if(BUILD_TESTING AND TARGET faset_render)
+  add_executable(faset_render_gpu_acceptance_tests
+    "${PROJECT_SOURCE_DIR}/tests/render_gpu_acceptance_tests.cpp")
+  target_link_libraries(faset_render_gpu_acceptance_tests PRIVATE faset_render)
+  foreach(FASET_VISIBILITY_CASE empty capacity dense door shadow cut resize lod)
+    add_test(NAME "render_gpu_${FASET_VISIBILITY_CASE}"
+      COMMAND faset_render_gpu_acceptance_tests --case "${FASET_VISIBILITY_CASE}")
+    set_tests_properties("render_gpu_${FASET_VISIBILITY_CASE}"
+      PROPERTIES LABELS "gpu;p2" TIMEOUT 120)
+  endforeach()
+endif()