Fix: 修复火箭未爆炸bug（动态计算初速度确保必然到达目标高度）

public/js/effects/fireworks.js

@@ -18,13 +18,19 @@ const FireworksEffect = (() => {
          * @param {string}  color    爆炸颜色
          * @param {string}  type     爆炸类型：sphere / willow / ring
          */
-        constructor(x, targetY, color, type) {
+        constructor(x, targetY, color, type, canvasHeight) {
             this.x = x;
-            this.y = 9999; // 在 start() 里设置为 canvas.height
+            this.y = canvasHeight; // 从画布底部出发
             this.targetY = targetY;
             this.color = color;
             this.type = type;
-            this.vy = -(12 + Math.random() * 4); // 上升速度
+
+            // 根据飞行距离动态计算初始速度，保证必然到达目标高度
+            // 等比级数求和：total = vy / (1 - 0.98) = vy × 50
+            // 加 10%~20% 余量，使火箭略微超过目标再触发爆炸（更真实）
+            const dist = canvasHeight - targetY;
+            this.vy = -(dist / 50) * (1.1 + Math.random() * 0.15);
+
             this.trail = []; // 尾迹历史坐标
             this.exploded = false;
             this.done = false;
@@ -255,8 +261,7 @@ const FireworksEffect = (() => {
             const ty = h * (0.08 + Math.random() * 0.45);
             const color = COLORS[Math.floor(Math.random() * COLORS.length)];
             const type = TYPES[Math.floor(Math.random() * TYPES.length)];
-            const rocket = new Rocket(x, ty, color, type);
-            rocket.y = h; // 从底部发射
+            const rocket = new Rocket(x, ty, color, type, h); // 传入画布高度
             rockets.push(rocket);
             launchCnt++;
         }, 600);