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/preset-controller.js

@@ -0,0 +1,35 @@
+export default class PresetController {
+  constructor(presetStore) {
+    this.presetStore = presetStore;
+    this.previousPreset = "";
+    this.currentPreset = "";
+  }
+  getName() {
+    return Object.keys(this.presetStore);
+  }
+  set(newPreset, currentAudioSource, currentAudioVolume) {
+    let newPresetData = JSON.parse(JSON.stringify(this.presetStore[newPreset]));
+    if (this.previousPreset) {
+      if (
+        currentAudioSource &&
+        this.presetStore[this.previousPreset].audioOptions.source !==
+          currentAudioSource
+      ) {
+        newPresetData.audioOptions.source = currentAudioSource;
+      }
+      if (
+        currentAudioVolume ||
+        (currentAudioVolume === 0 &&
+          this.presetStore[this.previousPreset].audioOptions.volume !==
+            currentAudioVolume)
+      ) {
+        newPresetData.audioOptions.volume = currentAudioVolume;
+      }
+    }
+    if (this.currentPreset) {
+      this.previousPreset = this.currentPreset;
+    }
+    this.currentPreset = newPreset;
+    return newPresetData;
+  }
+}