BetterNether

Fixes

• CityPiece/DestructionPiece shared a MutableBlockPos cursor across chunks under parallel worldgen (BetterNether#309)
• Custom reagents were accepted by a vanilla brewing stand but never brewed
• Hook mushroom turned any potion into healing, not just awkward
• Repair flaming ruby gear with gloomsculk crystals

Validation

• ✅ BiomesOPlenty + Terralith (BiomesOPlenty-fabric-26.2-26.2.0.0.26.jar, Terralith_26.2_v2.6.4.jar, GlitchCore-fabric-26.2-26.2.0.0.0.jar, TerraBlender-fabric-26.2-26.2.0.0.2.jar, lithostitched-1.7.13-fabric-26.2.jar, tested: gametest+worldgen)
• ✅ Incendium alone (Incendium_Legacy_26.2_v5.5.0.jar, tested: gametest+worldgen)
• ✅ Nullscape alone (Nullscape_26.2_v1.2.20.jar, tested: gametest+worldgen)
• ✅ BOP + Terralith + Incendium + Nullscape (BiomesOPlenty-fabric-26.2-26.2.0.0.26.jar, Terralith_26.2_v2.6.4.jar, GlitchCore-fabric-26.2-26.2.0.0.0.jar, TerraBlender-fabric-26.2-26.2.0.0.2.jar, lithostitched-1.7.13-fabric-26.2.jar, Incendium_Legacy_26.2_v5.5.0.jar, Nullscape_26.2_v1.2.20.jar, tested: gametest+worldgen)