rendering: formalize shader keyword metadata contract

engine/src/Resources/BuiltinResources.cpp

@@ -658,6 +658,11 @@ size_t CalculateBuiltinShaderMemorySize(const Shader& shader) {
             memorySize += binding.name.Length();
             memorySize += binding.semantic.Length();
         }
+        for (const ShaderKeywordDeclaration& declaration : pass.keywordDeclarations) {
+            for (const Containers::String& option : declaration.options) {
+                memorySize += option.Length();
+            }
+        }
         for (const ShaderStageVariant& variant : pass.variants) {
             memorySize += variant.entryPoint.Length();
             memorySize += variant.profile.Length();