Ice Caves Backport 0.1.9

Includes the previously unpublished Vanilla Backport compatibility fixes and optional duplicate-icicle integration.

Fixes and Vanilla Backport support

• Fixed the startup crash alongside Vanilla Backport 1.2.1 caused by duplicate minecraft:trapezoid registration. The legacy implementation codec now has a private ID; native content retains its minecraft IDs. Neither mod is disabled.
• Frostbite kills now count toward Monster Hunter and Monsters Hunted, preserving other mods' advancement criteria, displays and rewards.
• Packed ice bricks and chiseled packed ice now use Sulfur Cubes' native fast-sliding food archetype through additive tags. Unsuitable blocks are not incorrectly added as food.
• Restored missing 1.20.1-format entity tags for Frostbite and Ice Balls, including zombie classification, powder-snow walking and brittle-ice immunity.

Optional duplicate-icicle compatibility

• Added commented config/ice_caves_backport-compat.json5, with a global mode and per-mod overrides for YUNG's Cave Biomes, Immersive Weathering and Frostiful.
• OFF (default): leaves those mods' blocks, items, recipes and generation unchanged.
• REPLACE: converts supported duplicate icicle items and loaded blocks to minecraft:icicle, preserving compatible direction, thickness and waterlogging. Adapts data-driven recipe, loot, advancement and item-tag references. Unique tools and building materials remain registered.
• RESPECT: retains original blocks, mechanics and generation, distinguishes default names and adds reversible, count-preserving crafting conversions. It does not disable either mod's world generation.
• Replacement is deferred and limited per tick; unloaded chunks are never force-loaded. Creative tabs handle repeated converted items safely.
• Winterly's wall-facing icicles and unknown blocks are deliberately excluded because they have no matching native counterpart.

Back up worlds before REPLACE. Saved conversions are permanent; OFF does not undo them. REPLACE substitutes native mechanics for source-specific mechanics. Restart after configuration changes and use matching settings on clients and servers.

No supported third-party mod is required or bundled. Integration activates only when the exact supported block and item exist.