fix: anvil name components changes [EcoHub-14] - #564

Component.unstyled() wrapped every name/lore line in an empty parent
component (color(null), italic false) via append(), so the CUSTOM_NAME
data component ended up as {"text":"","extra":[{"text":"Name"}]}
instead of a flat {"text":"Name"}. Anvil renames (and any other
FastItemStack.displayName/lore write) go through this path, so every
renamed item's custom_name diverged from vanilla's format, breaking
resource packs that key item models off custom_name.

Use decorationIfAbsent(ITALIC, FALSE) directly on the component instead
of wrapping it, which only resets the implicit italic on custom names
without introducing a synthetic parent/child structure.