Eternal Blizzard Creatures 0.5.7
Minecraft 1.21.11 / Fabric / Java 21

Snow Explorer: Packed Ice for the Silent Altar
- Every Snow Explorer now shows a guaranteed first-row sale of 4 Packed Ice for
  2 Emeralds, with 16 uses and 3 villager experience.
- The offer is repaired when Minecraft actually retrieves the merchant offer
  list. This also covers existing villagers whose offers are loaded or rebuilt
  after the entity was prepared.
- Existing book, Sigil and other offers stay in their current relative order.
  Their prices, demand, discounts, used stock and remaining uses are preserved.
- If an Explorer already has a Packed Ice sale, that exact offer is promoted to
  the first row without being recreated. Repeated trade screens never duplicate
  the offer or refill sold-out stock.
- Ordinary villagers, other merchant entities and client-side offer access are
  unchanged.

Ritual supplies
The Silent Altar uses 8 Packed Ice around its Chiseled Stone Brick centre. The
Cracked Winter Sigil recipe uses another 4 Packed Ice. Three purchases cover the
12 blocks needed for both steps at the base price, costing 6 Emeralds.

Installation
Replace Creatures 0.5.6 with this JAR on the server and clients, then restart
the server or Minecraft. Keep only one Creatures JAR in the mods folder. Existing
Survival, Bosses and Atmosphere JARs are unaffected.

Verification
- The live 1.21.11 MerchantEntity.getOffers() method and the trade-screen call
  were checked against the official Minecraft 1.21.11 bytecode and intermediary
  mappings. The new server mixin targets the exact RETURN of that method.
- 217 lifecycle assertions passed, including the reproduced 0.5.6 failure where
  a later offer-list replacement removed the appended sale. The checks cover
  lazy generation, restored lists, existing stock, discounts, demand, duplicate
  prevention, first-row order and client guards.
- Only two runtime helper classes and the mixin list are added. All previous
  runtime classes, textures, recipes, tags and other data remain byte-identical
  to the exact 0.5.6 input JAR.
- ASM/JVM verification, JSON parsing, class-version checks and ZIP integrity
  checks passed. No compiled test fixtures are included in the mod.
- No live Minecraft playtest was run in this environment.

Build notes
This is a targeted binary update of the supplied compiled Creatures mod. Patch
sources, mappings and isolated lifecycle tests are under
META-INF/sources/update-0.5.7/. Runtime requirements remain Fabric 1.21.11 and
Java 21.
