chore: 基线 — 已发布壁纸现状原样入库（未做任何改动）

dist/ 为 Wallpaper Engine 网页壁纸「【崩坏：星穹铁道】昔涟」(workshopid 3604974793, version 2)，
含两套预设 xilian / kv37，总计 105.1MB。本次提交不做任何修改，仅作为后续优化的对拍基线。

dist/scripts/audio-controller.js

@@ -0,0 +1,64 @@
+export default class AudioController {
+  constructor(audioId, options = {}) {
+    this.audio = document.getElementById(audioId);
+    this.audio.src = options.source;
+    this.audio.volume = options.volume;
+    this.audio.loop = true;
+    this.isPlaying = false;
+    this.isChangingSource = false;
+    this.previousSource = null;
+  }
+  play() {
+    if (this.isPlaying) {
+      return;
+    }
+    if (this.isChangingSource) {
+      return;
+    }
+    if (this.audio) {
+      setTimeout(() => {
+        this.isPlaying = true;
+        this.audio.play().catch((error) => {
+          this.isPlaying = false;
+          this.changeSource(this.previousSource);
+        });
+      }, 200);
+    }
+  }
+  pause() {
+    this.audio.pause();
+    this.isPlaying = false;
+  }
+  changeSource(newSource) {
+    if (this.isChangingSource) {
+      return;
+    }
+    if (this.audio) {
+      this.isChangingSource = true;
+      this.pause();
+      this.previousSource = this.audio.src;
+      this.audio.src = newSource;
+      this.isChangingSource = false;
+      this.play();
+    }
+  }
+  changeVolume(newVolume) {
+    const clampedVolume = Math.max(0, Math.min(1, newVolume));
+    this.audio.volume = clampedVolume;
+    this.changeStateByVolume();
+  }
+  changeStateByVolume() {
+    const currentVolume = this.audio.volume;
+    if (currentVolume > 0 && !this.isPlaying) {
+      this.play();
+    } else if (currentVolume <= 0 && this.isPlaying) {
+      this.pause();
+    }
+  }
+  changeOptions(newOptions) {
+    const newSource = newOptions.source;
+    const newVolume = newOptions.volume;
+    this.changeSource(newSource);
+    this.changeVolume(newVolume);
+  }
+}