feat: Add texture rendering endpoints and service methods

- Introduced new API endpoints for rendering textures, avatars, capes, and previews, enhancing the texture handling capabilities.
- Implemented corresponding service methods in the TextureHandler to process rendering requests and return appropriate responses.
- Updated the TextureRenderService interface to include methods for rendering textures, avatars, and capes, along with their respective parameters.
- Enhanced error handling for invalid texture IDs and added support for different rendering types and formats.
- Updated go.mod to include the webp library for image processing.

internal/service/interfaces.go

@@ -141,6 +141,69 @@ type SecurityService interface {
 	ClearVerifyAttempts(ctx context.Context, email, codeType string) error
 }
 
+// TextureRenderService 纹理渲染服务接口
+type TextureRenderService interface {
+	// RenderTexture 渲染纹理为预览图
+	RenderTexture(ctx context.Context, textureID int64, renderType RenderType, size int, format ImageFormat) (*RenderResult, error)
+	// RenderTextureFromData 从原始数据渲染纹理
+	RenderTextureFromData(ctx context.Context, textureData []byte, renderType RenderType, size int, format ImageFormat, isSlim bool) ([]byte, string, error)
+	// GetRenderURL 获取渲染图的URL
+	GetRenderURL(textureID int64, renderType RenderType, size int, format ImageFormat) string
+	// DeleteRenderCache 删除渲染缓存
+	DeleteRenderCache(ctx context.Context, textureID int64) error
+	// RenderAvatar 渲染头像（支持2D/3D模式）
+	RenderAvatar(ctx context.Context, textureID int64, size int, mode AvatarMode, format ImageFormat) (*RenderResult, error)
+	// RenderCape 渲染披风
+	RenderCape(ctx context.Context, textureID int64, size int, format ImageFormat) (*RenderResult, error)
+	// RenderPreview 渲染预览图（类似Blessing Skin的preview功能）
+	RenderPreview(ctx context.Context, textureID int64, size int, format ImageFormat) (*RenderResult, error)
+}
+
+// RenderType 渲染类型
+type RenderType string
+
+const (
+	RenderTypeFront     RenderType = "front"     // 正面
+	RenderTypeBack      RenderType = "back"      // 背面
+	RenderTypeFull      RenderType = "full"      // 全身
+	RenderTypeHead      RenderType = "head"      // 头像
+	RenderTypeIsometric RenderType = "isometric" // 等距视图
+)
+
+// ImageFormat 输出格式
+type ImageFormat string
+
+const (
+	ImageFormatPNG  ImageFormat = "png"
+	ImageFormatWEBP ImageFormat = "webp"
+)
+
+// AvatarMode 头像模式
+type AvatarMode string
+
+const (
+	AvatarMode2D AvatarMode = "2d" // 2D头像
+	AvatarMode3D AvatarMode = "3d" // 3D头像
+)
+
+// TextureType 纹理类型
+type TextureType string
+
+const (
+	TextureTypeSteve TextureType = "steve" // Steve皮肤
+	TextureTypeAlex  TextureType = "alex"  // Alex皮肤
+	TextureTypeCape  TextureType = "cape"  // 披风
+)
+
+// RenderResult 渲染结果（附带缓存/HTTP头信息）
+type RenderResult struct {
+	URL          string
+	ContentType  string
+	ETag         string
+	LastModified time.Time
+	Size         int64
+}
+
 // Services 服务集合
 type Services struct {
 	User         UserService