fix: add debounce to theme toggle to prevent flash-back

static/js/utils/theme.js

@@ -1,5 +1,6 @@
 const Theme = {
     _current: 'dark',
+    _toggling: false,
 
     init() {
         this._current = localStorage.getItem('turbosu-theme') || 'dark';
@@ -7,8 +8,11 @@ const Theme = {
     },
 
     toggle() {
+        if (this._toggling) return;
+        this._toggling = true;
         this._current = this._current === 'dark' ? 'light' : 'dark';
         this.apply();
+        setTimeout(() => { this._toggling = false; }, 200);
     },
 
     apply() {