fix: RHI单元测试修复与命名规范统一

RHI抽象层测试修复:
- OpenGL Shader: 空描述符正确返回nullptr
- OpenGL Texture: 修复TextureType映射(case 2/3)
- OpenGL Buffer: 设置stride和state支持
- OpenGL Texture: 添加Format和State支持
- OpenGL SwapChain: 修复IsFullscreen硬编码false问题

命名规范统一( snake_case + _test后缀):
- D3D12_Minimal -> d3d12_minimal_test
- D3D12_Triangle -> d3d12_triangle_test
- D3D12_Quad -> d3d12_quad_test
- D3D12_Sphere -> d3d12_sphere_test
- OpenGL_Minimal -> opengl_minimal_test
- OpenGL_Triangle -> opengl_triangle_test
- OpenGL_Quad -> opengl_quad_test
- OpenGL_Sphere -> opengl_sphere_test
- CTest名称去掉_Integration后缀

测试结果: 138个测试中从21个失败减少到16个失败

tests/RHI/unit/CMakeLists.txt

@@ -18,11 +18,11 @@ set(TEST_SOURCES
     ${CMAKE_SOURCE_DIR}/tests/opengl/package/src/glad.c
 )
 
-add_executable(rhi_tests ${TEST_SOURCES})
+add_executable(rhi_unit_tests ${TEST_SOURCES})
 
-target_compile_definitions(rhi_tests PRIVATE XCENGINE_SUPPORT_OPENGL)
+target_compile_definitions(rhi_unit_tests PRIVATE XCENGINE_SUPPORT_OPENGL)
 
-target_link_libraries(rhi_tests PRIVATE
+target_link_libraries(rhi_unit_tests PRIVATE
     d3d12
     dxgi
     d3dcompiler
@@ -32,7 +32,7 @@ target_link_libraries(rhi_tests PRIVATE
     GTest::gtest_main
 )
 
-target_include_directories(rhi_tests PRIVATE
+target_include_directories(rhi_unit_tests PRIVATE
     ${CMAKE_CURRENT_SOURCE_DIR}/fixtures
     ${PROJECT_ROOT_DIR}/engine/include
     ${PROJECT_ROOT_DIR}/engine/src
@@ -40,4 +40,4 @@ target_include_directories(rhi_tests PRIVATE
 )
 
 include(GoogleTest)
-gtest_discover_tests(rhi_tests)
+gtest_discover_tests(rhi_unit_tests)