extend user block fields check

src/voxels/Block.cpp

@@ -1,5 +1,6 @@
 #include "Block.hpp"
 
+#include <set>
 #include <utility>
 
 #include "core_defs.hpp"
@@ -141,3 +142,10 @@ void Block::cloneTo(Block& dst) {
     dst.inventorySize = inventorySize;
     dst.tickInterval = tickInterval;
 }
+
+static std::set<std::string, std::less<>> RESERVED_BLOCK_FIELDS {
+};
+
+bool Block::isReservedBlockField(std::string_view view) {
+    return RESERVED_BLOCK_FIELDS.find(view) != RESERVED_BLOCK_FIELDS.end();
+}

src/voxels/Block.hpp

@@ -26,7 +26,7 @@ inline constexpr uint FACE_PZ = 5;
 /// complex hitboxes
 inline constexpr uint BLOCK_AABB_GRID = 16;
 
-inline constexpr size_t MAX_BLOCK_FIELDS_SIZE = 240;
+inline constexpr size_t MAX_USER_BLOCK_FIELDS_SIZE = 240;
 
 inline std::string DEFAULT_MATERIAL = "base:stone";
 
@@ -222,6 +222,8 @@ public:
     ~Block();
 
     void cloneTo(Block& dst);
+
+    static bool isReservedBlockField(std::string_view view);
 };
 
 inline glm::ivec3 get_ground_direction(const Block& def, int rotation) {