fix: 碎冰规则改为只保留水源变碎冰，流动水不再中断水流

原实现直接拦截 setBlockAndUpdate 并返回 false，导致邻接蓝冰的流动水被 shouldSpreadLiquid 的 return false 短路，水流扩散停止。
改为在 BlockState#is(BLUE_ICE) 判断处做手脚：规则开启且当前水非水源时让 is 返回 false，原版整个变碎冰分支被跳过，shouldSpreadLiquid 正常返回 true，水流照常扩散。

src/main/java/com/github/zly2006/carpetslsaddition/mixin/block/MixinFlowingWaterBrittleIce.java

@@ -8,10 +8,12 @@ import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.Blocks;
 import net.minecraft.world.level.block.LiquidBlock;
 import net.minecraft.world.level.block.state.BlockState;
-import net.minecraft.world.level.material.FlowingFluid;
 import net.minecraft.world.level.material.FluidState;
 import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Unique;
 import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 
 /**
  * 26.4 快照加入的“碎冰”（Brittle Ice）机制：
@@ -19,32 +21,49 @@ import org.spongepowered.asm.mixin.injection.At;
  * 会把当前水流方块替换为碎冰。
  *
  * 开启 noBrittleIceFromFlowingWater 规则后：
- * 仅当当前水方块处于“下落”状态（FlowingFluid#isFalling，即非水源且流体等级=8）时，
+ * 只有「水源方块」贴蓝冰时照常变碎冰；所有「流动的水」（横向、下落）都不再变碎冰，
- * 才允许它被替换为碎冰；纯横向流动的水不再触发该替换，以保护蓝冰水道。
+ * 且水流扩散不受影响。
  *
- * 实现方式：用 WrapOperation 包住 shouldSpreadLiquid 里对 Level#setBlockAndUpdate 的调用，
+ * 实现：原版判断邻居是不是蓝冰用 BlockState#is(Blocks.BLUE_ICE)，一旦命中就
- * 只在「目标方块是 BRITTLE_ICE」且「当前水不是下落状态」时跳过该次设置，其余调用原样放行。
+ * 变碎冰并 return false（中断扩散）。本 mixin 让流动水贴蓝冰时这次 is() 返回 false，
+ * 整个“变碎冰”分支被跳过，shouldSpreadLiquid 正常返回 true，水流照常扩散。
+ * 位置信息通过 ThreadLocal 从方法入口传入。
  */
 @Mixin(LiquidBlock.class)
 public class MixinFlowingWaterBrittleIce {
-    @WrapOperation(
+    @Unique
-        method = "shouldSpreadLiquid",
+    private static final ThreadLocal<Level> CURRENT_LEVEL = new ThreadLocal<>();
-        at = @At(value = "INVOKE", target = "Lnet/minecraft/world/level/Level;setBlockAndUpdate(Lnet/minecraft/core/BlockPos;Lnet/minecraft/world/level/block/state/BlockState;)Z")
+    @Unique
-    )
+    private static final ThreadLocal<BlockPos> CURRENT_POS = new ThreadLocal<>();
-    private boolean wrapSetBlockAndUpdate(Level level, BlockPos pos, BlockState newState,
+
-                                          Operation<Boolean> original) {
+    @Inject(method = "shouldSpreadLiquid", at = @At("HEAD"))
-        if (SLSCarpetSettings.noBrittleIceFromFlowingWater
+    private void captureArgs(Level level, BlockPos pos, BlockState state, CallbackInfoReturnable<Boolean> cir) {
-            && newState.is(Blocks.BRITTLE_ICE)) {
+        CURRENT_LEVEL.set(level);
-            FluidState current = level.getFluidState(pos);
+        CURRENT_POS.set(pos);
-            if (!isFalling(current)) {
-                return false; // 跳过把这块水替换成碎冰
-            }
-        }
-        return original.call(level, pos, newState);
     }
 
-    private static boolean isFalling(FluidState fluid) {
+    @WrapOperation(
-        if (!(fluid.getType() instanceof FlowingFluid flowing)) return false;
+        method = "shouldSpreadLiquid",
-        return flowing.isFalling(fluid);
+        at = @At(value = "INVOKE", target = "Lnet/minecraft/world/level/block/state/BlockState;is(Ljava/lang/Object;)Z")
+    )
+    private boolean wrapIsBlueIce(BlockState instance, Object target, Operation<Boolean> original) {
+        Boolean result = original.call(instance, target);
+        if (!result) return false;
+        // 只有判断目标确实是 BLUE_ICE 时才可能干预
+        if (!(target instanceof net.minecraft.world.level.block.Block b) || !b.equals(Blocks.BLUE_ICE)) {
+            return true;
+        }
+        if (!SLSCarpetSettings.noBrittleIceFromFlowingWater) return true;
+
+        Level level = CURRENT_LEVEL.get();
+        BlockPos pos = CURRENT_POS.get();
+        if (level == null || pos == null) return true;
+
+        FluidState current = level.getFluidState(pos);
+        // 流动水（非水源）不让它触发碎冰替换
+        if (!current.isSource()) {
+            return false;
+        }
+        return true;
     }
 }