[Feat] (MG_Backend): wire primitive restart into both backends; detect dualSrcBlend

Make GL_PRIMITIVE_RESTART[_FIXED_INDEX] actually take effect at draw time,
following the detect-at-init / POST / fallback-or-hard-fail discipline.

DirectVulkan:
- Thread primitiveRestartEnable through the pipeline (payload + hash +
  input-assembly), set from the GL_PRIMITIVE_RESTART / _FIXED_INDEX caps.
- Detect and enable primitiveTopologyListRestart
  (VK_EXT_primitive_topology_list_restart) at device creation; cache it.
  Strip/fan restart needs no feature; a *list* topology with restart and
  no feature hard-fails at the draw with the reason.
- Vulkan only restarts on the fixed all-ones index value, so an arbitrary
  GL_PRIMITIVE_RESTART index that is not that value hard-fails in
  UploadAndBindIndexBuffer (where the index type is known).
- Also detect+enable and cache the dualSrcBlend base feature (groundwork
  for GL_SRC1_* dual-source blending).

DirectGLES:
- Sync GL_PRIMITIVE_RESTART_FIXED_INDEX from either restart cap (GLES core
  has only the fixed-index form); an arbitrary non-fixed index hard-fails
  in the indexed draw paths with the reason.

POST: dualSrcBlend and primitiveTopologyListRestart capability rows (Pass
when supported, Warn with the fallback/hard-fail consequence otherwise).

Library builds clean; SanityTest 31/31. (The actual restart rendering and
the hard-fail paths need a real GPU and are not runtime-testable here.)

MobileGL/MG_Backend/DirectVulkan/Renderer/PipelineFactory.h

@@ -29,6 +29,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             VkSampleCountFlagBits rasterizationSamples = VK_SAMPLE_COUNT_1_BIT;
             Uint32 subpass = 0;
             VkPrimitiveTopology topology = VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST;
+            Bool primitiveRestartEnable = false;
             VkPolygonMode polygonMode = VK_POLYGON_MODE_FILL;
             VkCullModeFlags cullMode = VK_CULL_MODE_BACK_BIT;
             VkFrontFace frontFace = VK_FRONT_FACE_CLOCKWISE;