删除服务端材质渲染功能及system_config表，转为环境变量配置，初步配置管理员功能

pkg/database/cache.go

@@ -306,11 +306,6 @@ func (b *CacheKeyBuilder) TextureList(userID int64, page int) string {
 	return fmt.Sprintf("%stexture:user:%d:page:%d", b.prefix, userID, page)
 }
 
-// TextureRender 构建材质渲染缓存键
-func (b *CacheKeyBuilder) TextureRender(textureID int64, renderType string, size int) string {
-	return fmt.Sprintf("%stexture:render:%d:%s:%d", b.prefix, textureID, renderType, size)
-}
-
 // Token 构建令牌缓存键
 func (b *CacheKeyBuilder) Token(accessToken string) string {
 	return fmt.Sprintf("%stoken:%s", b.prefix, accessToken)