feat: 适配 26.4 并新增横向流动水不产生碎冰规则

- gradle.properties 切换到 26.4-snapshot-4 / Loom 1.19-SNAPSHOT / Loader 0.20.0 / Fabric API 0.163.0+26.4 / Carpet 26.4-beta-3
- 新增规则 noBrittleIceFromFlowingWater，默认关闭
- LiquidBlock#shouldSpreadLiquid 用 WrapOperation 拦截碎冰替换：只有竖直下落的水（FlowingFluid#isFalling）才允许把邻接蓝冰转成碎冰，横向流动的水跳过
- 补 zh_cn/en_us 规则名与描述

src/main/resources/assets/slsaddition/lang/en_us.json

@@ -76,5 +76,7 @@
   "carpet.rule.stackableVehicles.name": "Stackable vehicles",
   "carpet.rule.stackableVehicles.desc": "Minecarts and boats can stack up to 64, auto-merging on pickup",
   "carpet.rule.slsBoardEnabled.name": "Enable boards",
-  "carpet.rule.slsBoardEnabled.desc": "Allow players to use /slsboard to show death/mining leaderboards"
+  "carpet.rule.slsBoardEnabled.desc": "Allow players to use /slsboard to show death/mining leaderboards",
+  "carpet.rule.noBrittleIceFromFlowingWater.name": "No brittle ice from flowing water",
+  "carpet.rule.noBrittleIceFromFlowingWater.desc": "Only water flowing straight down onto blue ice forms brittle ice. Horizontally flowing water will not."
 }