fix: 调整技能施放时的高度偏移量从50降至30

统一技能施放和目标检测时的高度偏移量，使逻辑更加一致

assets/script/game/hero/SACastSystem.ts

@@ -253,7 +253,7 @@ export class SACastSystem extends ecs.ComblockSystem implements ecs.ISystemUpdat
         
         // 获取施法者位置作为起始位置
         const startPos = caster.node.position.clone();
-        startPos.y += 50;
+        startPos.y += 30;
         
         const targetPos = targets[0]; // 使用第一个目标位置
         // console.log(`[SACastSystem]: ${s_uuid}, 起始位置: ${startPos}, 目标位置: ${targetPos}`);
@@ -329,7 +329,7 @@ export class SACastSystem extends ecs.ComblockSystem implements ecs.ISystemUpdat
             if (model.is_dead) return false;
             if (model.fac === fac) return false;
             const pos = view.node.position.clone();
-            pos.y += 50;
+            pos.y += 30;
             const dist = Math.abs(currentPos.x - pos.x);
             if (dist <= range) {
                 const laneBias = Math.abs(currentPos.y - pos.y);