Don't declare colorWriteEnable dynamic state on depth-only pipelines (#160)

fix(gpu): drop colorWriteEnable dynamic state on depth-only pipelines

Pipelines were created with VK_DYNAMIC_STATE_COLOR_WRITE_ENABLE_EXT
unconditionally on non-Apple platforms, but the draw path only calls
vkCmdSetColorWriteEnableEXT when there is at least one color attachment.
A depth-only draw therefore reached vkCmdDrawIndexed with the dynamic
state declared and never set, which violates
VUID-vkCmdDrawIndexed-None-07749.

With validation enabled the error is fatal, so any title that issues a
depth-only pass aborts. The launcher enables validation by default
(vulkan_validation_enabled = true), so this is the default configuration:
PAC-MAN WORLD Re-PAC crashes from the launcher while the same build runs
normally with --vulkan-validation false.

Gate the declaration on the same color_count the draw path uses. Both
sides read state.color_count from the same draw, so the two conditions
are now identical by construction.

src/graphics/host_gpu/renderer/pipeline/shaders.cpp

@@ -953,11 +953,17 @@ void CreatePipelineInternal(
 	    vk::DynamicState::eStencilReference,
 	    vk::DynamicState::eStencilWriteMask,
 #if !defined(__APPLE__)
+	    // Keep last so depth-only pipelines can omit this dynamic state.
 	    vk::DynamicState::eColorWriteEnableEXT, // unsupported by MoltenVK; static mask instead
 #endif
 	};
-	const auto dynamic_states_count =
+	auto dynamic_states_count =
 	    static_cast<uint32_t>(sizeof(dynamic_states) / sizeof(dynamic_states[0]));
+#if !defined(__APPLE__)
+	if (static_params.color_count == 0) {
+		dynamic_states_count--;
+	}
+#endif
 
 	vk::PipelineDynamicStateCreateInfo dynamic_state {};
 	dynamic_state.sType             = vk::StructureType::ePipelineDynamicStateCreateInfo;