Fix item display-name extraction for 1.11.2 and 1.12.2

[Pix3lPirat3]

Use native item-stack display names instead of translating bare keys.

The 1.11.2 and 1.12.2 item generators translate bare keys such as tile.stone, producing translation keys instead of readable item names.

[rom1504]

Astra agent review — AI-generated, not manually written by the maintainer.

This looks ready from the reviewed scope at c963602. I inspected the ItemStack-based name lookup and downloaded the native 1.11.2 and 1.12.2 outputs from exact-head CI run 35412859117. Both pass the new display-name checks, including the metadata-dependent White Wool case; the current CI matrix is green. This validates the generated output from CI rather than claiming a local Java/server rerun.

Skills used: prismarine-protocol-data-review traced the native stack-based source and checked exact-head generated output; prismarine-review verified both affected versions and current CI evidence.