fix(title): 预览区标题样式应用真实模板描边/阴影/背景值

问题：FrontendPreviewPlayer 渲染视频预览标题时，描边宽度/颜色、阴影偏移/模糊/颜色、背景色块都被硬编码（如黑描边2px、固定2px阴影、无背景），选模板后预览文字不显示模板真实样式（例如抖音爆款黄的8px黑描边只显示2px）。

修复：
- FrontendPreviewPlayer 扩展 titleSettings props，接收 strokeWidth/strokeColor/shadowOffsetX/Y/shadowBlur/shadowColor/bgEnabled/bgColor/bgPadding/bgRadius/lineHeight 字段
- 所有描边/阴影/背景值按容器等比缩放后用于 CSS
- CanvasPreviewGrid 传递 titleSettings 时补充上述字段，批量预览同步生效
- 删除不再使用的 titleScale 常量
- 数字人侧 PanelLipsyncPreview 已正确读字段，无需改动

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

@@ -140,7 +140,19 @@ const CanvasPreviewGrid: React.FC<CanvasPreviewGridProps> = ({
                   bold: titleSettings.bold,
                   italic: titleSettings.italic,
                   stroke: titleSettings.stroke,
+                  strokeWidth: titleSettings.strokeWidth,
+                  strokeColor: titleSettings.strokeColor,
                   shadow: titleSettings.shadow,
+                  shadowOffsetX: titleSettings.shadowOffsetX,
+                  shadowOffsetY: titleSettings.shadowOffsetY,
+                  shadowBlur: titleSettings.shadowBlur,
+                  shadowColor: titleSettings.shadowColor,
+                  bgEnabled: titleSettings.bgEnabled,
+                  bgColor: titleSettings.bgColor,
+                  bgPadding: titleSettings.bgPadding,
+                  bgRadius: titleSettings.bgRadius,
+                  lineHeight: titleSettings.lineHeight,
+                  maxCharsPerLine: titleSettings.maxCharsPerLine,
                   posX: titleSettings.posX,
                   posY: titleSettings.posY,
                 }}

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

@@ -36,6 +36,18 @@ interface FrontendPreviewPlayerProps {
     italic?: boolean
     stroke?: boolean
     shadow?: boolean
+    strokeWidth?: number
+    strokeColor?: string
+    shadowOffsetX?: number
+    shadowOffsetY?: number
+    shadowBlur?: number
+    shadowColor?: string
+    bgEnabled?: boolean
+    bgColor?: string
+    bgPadding?: number
+    bgRadius?: number
+    lineHeight?: number
+    maxCharsPerLine?: number
     posX?: number | null
     posY?: number | null
   }
@@ -249,10 +261,25 @@ const FrontendPreviewPlayer: React.FC<FrontendPreviewPlayerProps> = ({
   const titleSidePct = (TITLE_MARGIN_SIDE / playRes.width) * 100
   const titleTopPct = (TITLE_MARGIN_TOP / playRes.height) * 100
   const titleBottomPct = (TITLE_MARGIN_BOTTOM / playRes.height) * 100
-  const titleScale = containerHeight > 0 ? containerHeight / playRes.height : 1
-  const titleStrokeWidth = Math.max(1, 2 * titleScale)
-  const titleShadowBlur = 4 * titleScale
-  const titleShadowOffset = 2 * titleScale
+  // 标题缩放到容器：字号 px = (settings.size / playRes.height) * containerHeight
+  // 描边/阴影：读 titleSettings 真实值，按容器比例缩放
+  const titleStrokeWidth = Math.max(
+    1,
+    ((titleSettings?.strokeWidth ?? 4) / playRes.height) * containerHeight,
+  )
+  const titleStrokeColor = titleSettings?.strokeColor ?? "#000000"
+  const titleShadowBlur = ((titleSettings?.shadowBlur ?? 4) / playRes.height) * containerHeight
+  const titleShadowOffsetX =
+    ((titleSettings?.shadowOffsetX ?? 2) / playRes.height) * containerHeight
+  const titleShadowOffsetY =
+    ((titleSettings?.shadowOffsetY ?? 2) / playRes.height) * containerHeight
+  const titleShadowColor = titleSettings?.shadowColor ?? "rgba(0,0,0,0.8)"
+  const titleShadowStr = `${titleShadowOffsetX}px ${titleShadowOffsetY}px ${titleShadowBlur}px ${titleShadowColor}`
+  // 标题背景色块
+  const titleBgEnabled = !!titleSettings?.bgEnabled
+  const titleBgColor = titleSettings?.bgColor ?? "rgba(0,0,0,0.5)"
+  const titleBgPadding = ((titleSettings?.bgPadding ?? 12) / playRes.height) * containerHeight
+  const titleBgRadius = ((titleSettings?.bgRadius ?? 8) / playRes.height) * containerHeight
 
   // ── Video 播放器（默认路径，浏览器原生硬件解码） ──
   const {
@@ -561,14 +588,18 @@ const FrontendPreviewPlayer: React.FC<FrontendPreviewPlayerProps> = ({
                 color: titleSettings.color || "#ffffff",
                 fontWeight: titleSettings.bold ? 700 : 400,
                 fontStyle: titleSettings.italic ? "italic" : "normal",
-                lineHeight: 1.05,
+                lineHeight: titleSettings.lineHeight ?? 1.05,
                 wordBreak: "break-word",
                 WebkitTextStroke: titleSettings.stroke
-                  ? `${titleStrokeWidth}px #000000`
+                  ? `${titleStrokeWidth}px ${titleStrokeColor}`
                   : undefined,
-                textShadow: titleSettings.shadow
-                  ? `${titleShadowOffset}px ${titleShadowOffset}px ${titleShadowBlur}px rgba(0,0,0,0.8)`
+                textShadow: titleSettings.shadow ? titleShadowStr : undefined,
+                background: titleBgEnabled ? titleBgColor : undefined,
+                padding: titleBgEnabled
+                  ? `${titleBgPadding}px ${titleBgPadding * 1.5}px`
                   : undefined,
+                borderRadius: titleBgEnabled ? `${titleBgRadius}px` : undefined,
+                display: titleBgEnabled ? "inline-block" : undefined,
               }}
             >
               {(effectiveTitle || "").split(/[/／]/).map((part, i) => (