fix(hero cast): 调整敌我单位的目标选择逻辑

重构了SCastSystem中的目标查找逻辑，区分英雄和怪物的目标选择规则：英雄仅按X轴距离选择最近目标，怪物优先选择中路目标后再比较距离，同时更新了对应注释说明。

assets/script/game/hero/SCastSystem.ts

@@ -549,7 +549,8 @@ export class SCastSystem extends ecs.ComblockSystem implements ecs.ISystemUpdate
         const currentY = heroView.node.position.y;
         let nearest: HeroViewComp | null = null;
         let minDist = Infinity;
-        let foundSameLane = false;
+        let foundPreferredLane = false;
+        const isHero = heroAttrs.fac === FacSet.HERO;
 
         ecs.query(this.getHeroMatcher()).forEach(entity => {
             const attrs = entity.get(HeroAttrsComp);
@@ -562,23 +563,29 @@ export class SCastSystem extends ecs.ComblockSystem implements ecs.ISystemUpdate
             const distX = Math.abs(currentX - view.node.position.x);
             if (distX > maxRange) return;
             
-            const isSameLane = Math.abs(currentY - view.node.position.y) < 30; // 30为容差
+            if (isHero) {
+                // 英雄：单纯找X轴最近，无视路线
+                if (distX < minDist) {
+                    minDist = distX;
+                    nearest = view;
+                }
+            } else {
+                // 怪物：优先找中路目标
+                const isMidLane = Math.abs(view.node.position.y) < 30; // 0 是中路
 
-            // 如果之前找到了同路目标，且当前不是同路，直接跳过
+                if (foundPreferredLane && !isMidLane) return;
-            if (foundSameLane && !isSameLane) return;
 
-            // 如果当前是同路，且之前没找到同路，则强制替换（同路优先）
+                if (isMidLane && !foundPreferredLane) {
-            if (isSameLane && !foundSameLane) {
+                    foundPreferredLane = true;
-                foundSameLane = true;
+                    minDist = distX;
+                    nearest = view;
+                    return;
+                }
+
+                if (distX >= minDist) return;
                 minDist = distX;
                 nearest = view;
-                return;
             }
-
-            // 同等路况下比较距离
-            if (distX >= minDist) return;
-            minDist = distX;
-            nearest = view;
         });
         return nearest;
     }
@@ -586,7 +593,7 @@ export class SCastSystem extends ecs.ComblockSystem implements ecs.ISystemUpdate
     /**
      * 在施法距离内查找“最前排”敌人。
      * 依据施法者面向方向选择 x 轴上更前的目标。
-     * 考虑三路设计：同路优先
+     * 考虑三路设计：英雄找最前排，怪物优先找中路最前排
      */
     private findFrontEnemyInRange(heroAttrs: HeroAttrsComp, heroView: HeroViewComp, maxRange: number, nearestEnemy: HeroViewComp): HeroViewComp | null {
         if (!heroView.node || !nearestEnemy.node) return null;
@@ -595,7 +602,8 @@ export class SCastSystem extends ecs.ComblockSystem implements ecs.ISystemUpdate
         const direction = nearestEnemy.node.position.x >= currentX ? 1 : -1;
         let frontEnemy: HeroViewComp | null = null;
         let edgeX = direction > 0 ? Infinity : -Infinity;
-        let foundSameLane = false;
+        let foundPreferredLane = false;
+        const isHero = heroAttrs.fac === FacSet.HERO;
 
         ecs.query(this.getHeroMatcher()).forEach(entity => {
             const attrs = entity.get(HeroAttrsComp);
@@ -609,24 +617,38 @@ export class SCastSystem extends ecs.ComblockSystem implements ecs.ISystemUpdate
             const dist = Math.abs(currentX - enemyX);
             if (dist > maxRange) return;
 
-            const isSameLane = Math.abs(currentY - view.node.position.y) < 30;
+            if (isHero) {
-            if (foundSameLane && !isSameLane) return;
+                // 英雄：无视路线，找X轴最前的
-
+                if (direction > 0) {
-            if (isSameLane && !foundSameLane) {
+                    if (enemyX >= edgeX) return;
-                foundSameLane = true;
+                    edgeX = enemyX;
-                edgeX = enemyX;
+                } else {
+                    if (enemyX <= edgeX) return;
+                    edgeX = enemyX;
+                }
                 frontEnemy = view;
-                return;
-            }
-
-            if (direction > 0) {
-                if (enemyX >= edgeX) return;
-                edgeX = enemyX;
             } else {
-                if (enemyX <= edgeX) return;
+                // 怪物：优先找中路最前排的
-                edgeX = enemyX;
+                const isMidLane = Math.abs(view.node.position.y) < 30;
+                
+                if (foundPreferredLane && !isMidLane) return;
+
+                if (isMidLane && !foundPreferredLane) {
+                    foundPreferredLane = true;
+                    edgeX = enemyX;
+                    frontEnemy = view;
+                    return;
+                }
+
+                if (direction > 0) {
+                    if (enemyX >= edgeX) return;
+                    edgeX = enemyX;
+                } else {
+                    if (enemyX <= edgeX) return;
+                    edgeX = enemyX;
+                }
+                frontEnemy = view;
             }
-            frontEnemy = view;
         });
         return frontEnemy;
     }