feat(字体解耦): 解耦字体依赖，完善字体处理

ofdgo_renderer_svg_canvas.go

@@ -146,7 +146,7 @@ func (s *svgResourceRenderer) RenderText(text *canvas.Text, m canvas.Matrix) {
 	font := text.MostCommonFontFace().Font
 	resource, ok := s.renderer.canvasState().svgFontCache[font]
 	if !ok {
-		data := fontSFNTData(font.SFNT)
+		data := fontSFNTData(font.Tables)
 		resource = SVGFont{
 			Name:   fmt.Sprintf("ofdgo-%x-%d", sha256.Sum256(data), font.Style()),
 			Weight: font.Style().CSS(),