fix(phone-image): 修复字号倍数影响编辑器+刷新后丢失

- CSS变量 --pi-font-scale 仅在渲染容器上设置,不再全局污染
- Slider松手后立即保存配置,确保fontScale持久化

public/static/js/phone-image.js

@@ -80,7 +80,10 @@ var PhoneImageEngine = (function () {
      */
     function applyFontScale() {
         var scale = config.fontScale || 1;
-        document.documentElement.style.setProperty('--pi-font-scale', scale);
+        var preview = document.getElementById('render-preview');
+        if (preview) preview.style.setProperty('--pi-font-scale', scale);
+        var staging = document.getElementById('render-staging');
+        if (staging) staging.style.setProperty('--pi-font-scale', scale);
     }
 
     /**

view/admin/post/phone_image.html

@@ -351,7 +351,9 @@
                 var val = parseFloat($(this).val());
                 $scaleValue.text(val.toFixed(1) + 'x');
                 currentConfig.fontScale = val;
-                document.documentElement.style.setProperty('--pi-font-scale', val);
+                document.getElementById('render-preview').style.setProperty('--pi-font-scale', val);
+                var staging = document.getElementById('render-staging');
+                if (staging) staging.style.setProperty('--pi-font-scale', val);
                 PhoneImageEngine.updateConfig({ fontScale: val });
             });
 
@@ -359,6 +361,19 @@
             $slider.on('change', function() {
                 var val = parseFloat($(this).val());
                 doRender({ fontScale: val });
+                // 触发保存,确保字号倍数持久化
+                updateSaveState('saving');
+                PhoneImageEngine.saveConfig(postData.postId, {
+                    size: currentConfig.size,
+                    watermark: currentConfig.watermark,
+                    fontScale: currentConfig.fontScale || 1,
+                    content_html: PhoneImageEngine.getContentHtml()
+                }, saveConfigUrl).then(function(data) {
+                    if (data.output_id) lastOutputId = data.output_id;
+                    updateSaveState('saved');
+                }).catch(function(err) {
+                    updateSaveState('error');
+                });
             });
 
             // 初始化时更新 Slider 显示值