fix: launch rapid taps with concurrent exit animations

tests/exit-animations.test.js

@@ -0,0 +1,32 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { ExitAnimations } from '../src/exit-animations.js';
+import { Game, available } from '../src/core.js';
+import { LEVELS } from '../src/levels.js';
+import { layout } from '../src/geometry.js';
+import { drawScene } from '../src/renderer.js';
+
+test('rapid successful taps update immediately and render overlapping independent animations', () => {
+  const game = new Game(LEVELS[0]), exits = new ExitAnimations();
+  const tiles = available(game.level, game.tiles).slice(0, 2);
+  assert.equal(tiles.length, 2);
+  const before = game.moves;
+  exits.add(game.tap(tiles[0].id), 0, 1000);
+  exits.add(game.tap(tiles[1].id), 100, 1000);
+  assert.equal(game.moves, before - 2);
+  assert.equal(game.tap(tiles[0].id).status, 'missing');
+  const frames = exits.frames(200);
+  assert.deepEqual(frames.map(f => f.progress), [.2, .1]);
+  let sprites = 0;
+  const painter = { polygon(){}, line(){}, circle(){}, sprite(){sprites++;return true;} };
+  drawScene(painter, game.level, game.tiles, layout(game.level.cells, 390, 390), {exits:frames});
+  assert.equal(sprites, game.tiles.length + 2);
+  assert.equal(exits.frames(1000).length, 1);
+  assert.equal(exits.frames(1100).length, 0);
+  assert.equal(exits.active, false);
+  assert.ok(game.undo());assert.equal(game.moves, before - 1);
+});
+test('restart clears in-flight visuals', () => {
+  const exits = new ExitAnimations();exits.add({}, 0, 1000);exits.clear();
+  assert.deepEqual(exits.frames(100), []);
+});