Serene Seasons Better Winter

This update adds a general fix for hanging blocks under hidden winter leaves: apples now hide correctly, silk cocoons/silk cotton are also handled, and tree structure blocks are no longer hidden by mistake.

It also adds a synced server-side toggle (hide_blocks_attached_to_hidden_leaves) plus override tags (always_hide_when_attached_to_hidden_leaves / never_hide_when_attached_to_hidden_leaves) for fine control and multiplayer consistency.