feat(skill): add movement acceleration support for skills

1. 新增SMoveComp的isAccelerate字段控制加速逻辑
2. 添加技能配置is_accel字段启用加速效果
3. 实现二次方缓入加速曲线，兼顾起步速度与最终加速度
4. 为6001号技能默认开启加速效果并调整其移动类型为直线运动

assets/script/game/skill/SMoveComp.ts

@@ -69,6 +69,9 @@ export class SMoveDataComp extends ecs.Comp {
     bezierMidHeight: number = 200;
     bezierArc: number = 1;
     
+    /** 是否逐渐加速 (ease-in) */
+    isAccelerate: boolean = false;
+    
     /** 是否自动销毁（到达目标后） */
     autoDestroy: boolean = true;
     
@@ -80,6 +83,7 @@ export class SMoveDataComp extends ecs.Comp {
         this.bezierStartHeight = 30;
         this.bezierMidHeight = 200;
         this.bezierArc = 1;
+        this.isAccelerate = false;
         this.speed = 500;
         this.progress = 0;
         this.scale = 1;
@@ -181,14 +185,20 @@ export class SMoveDataComp extends ecs.Comp {
      * 根据移动类型计算当前位置
      */
     private calculateCurrentPosition() {
+        // 如果开启了逐渐加速，混合线性与二次方曲线 (如 0.7 * t^2 + 0.3 * t)
+        // 这样起步拥有 30% 的基础速度，不会显得完全静止，随后逐渐加速
+        const t = this.isAccelerate ? 
+            (this.progress * this.progress * 0.7 + this.progress * 0.3) : 
+            this.progress;
+
         switch (this.runType) {
             case RType.linear:
                 // 直线运动
-                Vec3.lerp(this.currentPos, this.startPos, this.targetPos, this.progress);
+                Vec3.lerp(this.currentPos, this.startPos, this.targetPos, t);
                 break;
                 
             case RType.bezier:
-                this.calculateBezierPosition(this.progress);
+                this.calculateBezierPosition(t);
                 break;
                 
             case RType.fixed:
@@ -198,7 +208,7 @@ export class SMoveDataComp extends ecs.Comp {
                 break;
                 
             default:
-                Vec3.lerp(this.currentPos, this.startPos, this.targetPos, this.progress);
+                Vec3.lerp(this.currentPos, this.startPos, this.targetPos, t);
                 break;
         }
     }