GroundZeroCore Resource Pack v29 - Missing GUI Item Fix

Built from v28.

Fixed:
- Missing saddle icon in Mount Shop.
- Missing donkey/chest-style mount icon.
- Missing compass/search icon references where present.
- Re-scanned all model texture references after fixing.

Important:
- Existing GroundZero custom textures were not replaced.
- Drugs, police, papers, casino and other working custom systems were preserved.
- Only missing item textures referenced by existing models were added.
- This avoids changing already-working GroundZero custom icons.

Validation:
{
  "created_fallback_count": 54,
  "missing_model_textures_after": 0,
  "json_errors_after": 0,
  "saddle_fixed": true,
  "chest_fixed": true,
  "compass_search_fixed": true,
  "gz_drugs_kept": true,
  "gz_police_kept": true,
  "gz_papers_kept": true,
  "gz_casino_kept": true
}

Created fallback textures:
[
  "assets/minecraft/textures/item/amethyst_shard.png",
  "assets/minecraft/textures/item/azalea_leaves.png",
  "assets/minecraft/textures/item/black_concrete.png",
  "assets/minecraft/textures/item/blaze_powder.png",
  "assets/minecraft/textures/item/blaze_rod.png",
  "assets/minecraft/textures/item/bone.png",
  "assets/minecraft/textures/item/bone_meal.png",
  "assets/minecraft/textures/item/book.png",
  "assets/minecraft/textures/item/brewing_stand.png",
  "assets/minecraft/textures/item/brown_dye.png",
  "assets/minecraft/textures/item/brown_mushroom.png",
  "assets/minecraft/textures/item/brush.png",
  "assets/minecraft/textures/item/cactus.png",
  "assets/minecraft/textures/item/carrot_on_a_stick.png",
  "assets/minecraft/textures/item/cauldron.png",
  "assets/minecraft/textures/item/chest.png",
  "assets/minecraft/textures/item/clay_ball.png",
  "assets/minecraft/textures/item/cod.png",
  "assets/minecraft/textures/item/compass.png",
  "assets/minecraft/textures/item/compass_00.png",
  "assets/minecraft/textures/item/composter.png",
  "assets/minecraft/textures/item/cookie.png",
  "assets/minecraft/textures/item/diamond_axe.png",
  "assets/minecraft/textures/item/emerald.png",
  "assets/minecraft/textures/item/flower_pot.png",
  "assets/minecraft/textures/item/ghast_tear.png",
  "assets/minecraft/textures/item/glass_bottle.png",
  "assets/minecraft/textures/item/glowstone_dust.png",
  "assets/minecraft/textures/item/gold_ingot.png",
  "assets/minecraft/textures/item/honey_bottle.png",
  "assets/minecraft/textures/item/iron_axe.png",
  "assets/minecraft/textures/item/iron_nugget.png",
  "assets/minecraft/textures/item/iron_pickaxe.png",
  "assets/minecraft/textures/item/knowledge_book.png",
  "assets/minecraft/textures/item/lead.png",
  "assets/minecraft/textures/item/magenta_dye.png",
  "assets/minecraft/textures/item/nether_star.png",
  "assets/minecraft/textures/item/paper.png",
  "assets/minecraft/textures/item/prismarine_crystals.png",
  "assets/minecraft/textures/item/quartz.png",
  "assets/minecraft/textures/item/rabbit_hide.png",
  "assets/minecraft/textures/item/red_dye.png",
  "assets/minecraft/textures/item/redstone_torch.png",
  "assets/minecraft/textures/item/repeater.png",
  "assets/minecraft/textures/item/rooted_dirt.png",
  "assets/minecraft/textures/item/saddle.png",
  "assets/minecraft/textures/item/scaffolding.png",
  "assets/minecraft/textures/item/search.png",
  "assets/minecraft/textures/item/search_icon.png",
  "assets/minecraft/textures/item/smoker.png",
  "assets/minecraft/textures/item/sugar.png",
  "assets/minecraft/textures/item/tripwire_hook.png",
  "assets/minecraft/textures/item/wheat_seeds.png",
  "assets/minecraft/textures/item/white_dye.png"
]

Remaining missing texture refs:
[]
