feat(hero): 添加英雄合并时的移动动画效果

实现英雄合并时的平滑移动动画，避免直接销毁的突兀感。为 Hero 类新增 mergeToBirthAndDestroy 方法，使英雄在销毁前移动到生成点。在 MissionHeroComp 中，合并逻辑改为异步等待动画完成，并添加防重复合并标志。

assets/script/game/hero/Hero.ts

@@ -151,6 +151,33 @@ export class Hero extends ecs.Entity {
             })
             .start();
     }
+
+    mergeToBirthAndDestroy(birthPos: Vec3, onDone?: () => void) {
+        const view = this.get(HeroViewComp);
+        const node = view?.node;
+        if (!node || !node.isValid) {
+            this.destroy();
+            if (onDone) onDone();
+            return;
+        }
+        const collider = node.getComponent(BoxCollider2D);
+        if (collider) {
+            collider.enabled = false;
+            collider.apply();
+        }
+        const currentPos = node.getPosition();
+        const targetPos = v3(birthPos.x, birthPos.y, 0);
+        const moveDistance = Vec3.distance(currentPos, targetPos);
+        const moveDuration = Math.max(0.12, Math.min(0.3, moveDistance / 1200));
+        Tween.stopAllByTarget(node);
+        tween(node)
+            .to(moveDuration, { position: targetPos })
+            .call(() => {
+                this.destroy();
+                if (onDone) onDone();
+            })
+            .start();
+    }
  
     /** 重置入口：复用 destroy 的释放流程 */
     reset() {

assets/script/game/map/MissionHeroComp.ts

@@ -20,6 +20,7 @@ export class MissionHeroCompComp extends CCComp {
     Friend_is_dead:boolean=false
     current_hero_uuid:number=0
     current_hero_num:number=-1
+    is_merging:boolean=false
     heros:any=[]
     onLoad(){
         this.on(GameEvent.FightReady,this.fight_ready,this)
@@ -55,24 +56,31 @@ export class MissionHeroCompComp extends CCComp {
 
     }
 
-    private call_hero(event: string, args: any){
+    private async call_hero(event: string, args: any){
         const uuid = Number(args?.uuid ?? 1001);
         const hero_lv = Math.max(1, Number(args?.hero_lv ?? 1));
         const aliveHeroes = this.getAliveHeroes();
         const mergeHeroes = this.pickMergeHeroes(aliveHeroes, uuid, hero_lv);
         if (mergeHeroes.length === 2) {
-            let sumAp = 0;
-            let sumHpMax = 0;
-            for (let i = 0; i < mergeHeroes.length; i++) {
-                const model = mergeHeroes[i].get(HeroAttrsComp);
-                if (!model) continue;
-                sumAp += model.ap;
-                sumHpMax += model.hp_max;
+            if (this.is_merging) return;
+            this.is_merging = true;
+            try {
+                let sumAp = 0;
+                let sumHpMax = 0;
+                for (let i = 0; i < mergeHeroes.length; i++) {
+                    const model = mergeHeroes[i].get(HeroAttrsComp);
+                    if (!model) continue;
+                    sumAp += model.ap;
+                    sumHpMax += model.hp_max;
+                }
+                let hero_pos = 0;
+                const landingPos:Vec3 = HeroPos[hero_pos].pos;
+                const spawnPos:Vec3 = v3(landingPos.x, landingPos.y + MissionHeroCompComp.HERO_DROP_HEIGHT, 0);
+                await this.mergeDestroyAtBirth(mergeHeroes, spawnPos);
+                this.addMergedHero(uuid, hero_lv + 1, sumAp, sumHpMax);
+            } finally {
+                this.is_merging = false;
             }
-            for (let i = 0; i < mergeHeroes.length; i++) {
-                mergeHeroes[i].destroy();
-            }
-            this.addMergedHero(uuid, hero_lv + 1, sumAp, sumHpMax);
             return;
         }
         this.addHero(uuid, hero_lv);
@@ -124,6 +132,26 @@ export class MissionHeroCompComp extends CCComp {
         return mergeHeroes;
     }
 
+    private mergeDestroyAtBirth(mergeHeroes: Hero[], spawnPos: Vec3): Promise<void> {
+        return new Promise((resolve) => {
+            let doneCount = 0;
+            const total = mergeHeroes.length;
+            if (total <= 0) {
+                resolve();
+                return;
+            }
+            const onDone = () => {
+                doneCount += 1;
+                if (doneCount >= total) {
+                    resolve();
+                }
+            };
+            for (let i = 0; i < mergeHeroes.length; i++) {
+                mergeHeroes[i].mergeToBirthAndDestroy(spawnPos, onDone);
+            }
+        });
+    }
+