fix: 字体加载后显式触发Canvas重绘

字体就绪后立即调用drawVideoTitle/drawNoVideoTitle
确保不依赖ResizeObserver才触发绘制

apps/web/src/pages/generate/components/PreviewVideoPanel.tsx

@@ -284,6 +284,13 @@ export const PreviewVideoPanel: React.FC<PreviewVideoPanelProps> = ({
     // 优先用 document.fonts.check 精确检测目标字体
     if (document.fonts.check(fontSpec)) {
       setFontLoaded(true)
+      // 字体已就绪，立即触发重绘
+      requestAnimationFrame(() => {
+        if (!cancelled) {
+          drawVideoTitle()
+          drawNoVideoTitle()
+        }
+      })
       return
     }
 
@@ -292,17 +299,24 @@ export const PreviewVideoPanel: React.FC<PreviewVideoPanelProps> = ({
       .load(fontSpec)
       .then(() => {
         if (!cancelled) {
-          // requestAnimationFrame 确保在下一帧绘制前字体已可用
           requestAnimationFrame(() => {
-            if (!cancelled) setFontLoaded(true)
+            if (!cancelled) {
+              setFontLoaded(true)
+              // 字体加载完成，显式触发重绘
+              drawVideoTitle()
+              drawNoVideoTitle()
+            }
           })
         }
       })
       .catch(() => {
-        // load 失败时回退到 fonts.ready
         if (!cancelled) {
           document.fonts.ready.then(() => {
-            if (!cancelled) setFontLoaded(true)
+            if (!cancelled) {
+              setFontLoaded(true)
+              drawVideoTitle()
+              drawNoVideoTitle()
+            }
           })
         }
       })