feat: instantFall改用ModifyArg直接改scheduleTick的delay参数

getDelayAfterPlace的hook可能被子类覆盖，改用ModifyArg拦截onPlace/updateShape的scheduleTick调用更可靠。

src/main/java/com/github/zly2006/carpetslsaddition/mixin/legacy/FallingBlockMixin.java

@@ -10,6 +10,7 @@ import net.minecraft.world.level.block.state.BlockState;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.injection.At;
 import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.ModifyArg;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 
@@ -19,16 +20,17 @@ import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
  * <p>1.12：世界装饰时短暂开启 instantFall，使重力方块在被更新时【立即】转为下落实体，
  * 而不等待 2gt 的计划刻延迟。26.1.2 已移除该 flag。
  *
- * <p>实现：
+ * <p>实现方式（双保险）：
  * <ul>
- *   <li>{@link #legacyDelayAfterPlace}：规则开启时把放置后的延迟改为 0，使下落尽快触发。</li>
- *   <li>{@link #legacyTick}：保留 tick 入口的标记逻辑。</li>
+ *   <li>{@link #legacyDelayAfterPlace}：把 {@code getDelayAfterPlace()} 的返回值改为 0。</li>
+ *   <li>{@link #legacyScheduleDelay}：直接拦截 {@code onPlace}/{@code updateShape} 里
+ *       对 {@code scheduleTick} 的 delay 参数，强制改为 0（更直接可靠）。</li>
  * </ul>
  */
 @Mixin(FallingBlock.class)
 public abstract class FallingBlockMixin {
 
-    /** instantFall：把"放置后延迟"改为 0（最小延迟）。 */
+    /** instantFall：把"放置后延迟"改为 0。 */
     @Inject(method = "getDelayAfterPlace", at = @At("HEAD"), cancellable = true)
     private void legacyDelayAfterPlace(CallbackInfoReturnable<Integer> cir) {
         if (SLSCarpetSettings.legacyExploitMode && SLSCarpetSettings.legacyInstantFall) {
@@ -36,6 +38,36 @@ public abstract class FallingBlockMixin {
         }
     }
 
+    /**
+     * instantFall：拦截 onPlace / updateShape 里 scheduleTick 的 delay 参数，强制为 0。
+     * 第 3 个参数（index=2）是延迟 tick 数。
+     */
+    @ModifyArg(
+            method = "onPlace",
+            at = @At(value = "INVOKE",
+                    target = "Lnet/minecraft/world/level/Level;scheduleTick(Lnet/minecraft/core/BlockPos;Lnet/minecraft/world/level/block/Block;I)V"),
+            index = 2
+    )
+    private int legacyScheduleDelayLevel(int delay) {
+        if (SLSCarpetSettings.legacyExploitMode && SLSCarpetSettings.legacyInstantFall) {
+            return 0;
+        }
+        return delay;
+    }
+
+    @ModifyArg(
+            method = "updateShape",
+            at = @At(value = "INVOKE",
+                    target = "Lnet/minecraft/world/level/ScheduledTickAccess;scheduleTick(Lnet/minecraft/core/BlockPos;Lnet/minecraft/world/level/block/Block;I)V"),
+            index = 2
+    )
+    private int legacyScheduleDelayAccess(int delay) {
+        if (SLSCarpetSettings.legacyExploitMode && SLSCarpetSettings.legacyInstantFall) {
+            return 0;
+        }
+        return delay;
+    }
+
     /** instantFall：tick 入口标记（供其他机制判断窗口）。 */
     @Inject(method = "tick", at = @At("HEAD"))
     private void legacyTick(BlockState state, ServerLevel level, BlockPos pos, RandomSource rand, CallbackInfo ci) {