refactor: Gitea 式目录改组，移除本分支 SPA 与杂项产物

将 model/service/handler/middleware 迁至 models/services/routers/api/modules/auth，并删除 frontend、embed_static、scripts 及误入库缓存/二进制。

Co-authored-by: Cursor <cursoragent@cursor.com>

services/image_webp.go

@@ -0,0 +1,152 @@
+package service
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"image"
+	"image/gif"
+	"io"
+	"mime/multipart"
+	"path/filepath"
+	"strings"
+
+	"github.com/KarpelesLab/gowebp"
+
+	// 注册解码器
+	_ "image/jpeg"
+	_ "image/png"
+
+	_ "golang.org/x/image/webp"
+)
+
+// 图片展示方案（上传时同时保留原图与 WebP，按此决定返回给前端的 URL）
+const (
+	ImageDeliveryWebP     = "webp"     // 使用 WebP（默认，省流量）
+	ImageDeliveryOriginal = "original" // 使用原图
+)
+
+const (
+	// UploadWebPQuality 上传衍生 WebP 有损质量（0–100）
+	UploadWebPQuality float32 = 82
+	// UploadWebPMethod 编码档位：3 速度与体积较均衡
+	UploadWebPMethod = 3
+	// ThumbWebPQuality 帖子预览图质量
+	ThumbWebPQuality float32 = 80
+)
+
+// preparedUpload 原图 + 可选 WebP 衍生
+type preparedUpload struct {
+	OrigExt         string // 含点，如 .jpg
+	OrigContentType string
+	OrigData        []byte
+	WebPData        []byte // 空表示无衍生（动图 GIF，或原图已是 WebP）
+}
+
+// prepareUploadImage 始终保留原图字节；静态图额外生成 WebP 衍生
+func prepareUploadImage(file *multipart.FileHeader) (*preparedUpload, error) {
+	ext := strings.ToLower(filepath.Ext(file.Filename))
+	if !allowedImageExt[ext] {
+		return nil, errors.New("仅支持 jpg/png/gif/webp 格式")
+	}
+	if ext == ".jpeg" {
+		ext = ".jpg"
+	}
+
+	src, err := file.Open()
+	if err != nil {
+		return nil, err
+	}
+	defer src.Close()
+
+	raw, err := io.ReadAll(src)
+	if err != nil {
+		return nil, err
+	}
+	if len(raw) == 0 {
+		return nil, errors.New("空图片文件")
+	}
+
+	out := &preparedUpload{
+		OrigExt:         ext,
+		OrigContentType: imageContentType(ext),
+		OrigData:        raw,
+	}
+
+	// 动图 GIF：只保留原文件
+	if ext == ".gif" && gifFrameCount(raw) > 1 {
+		return out, nil
+	}
+	// 上传已是 WebP：原图即 WebP，不再重复衍生
+	if ext == ".webp" {
+		return out, nil
+	}
+
+	img, _, err := image.Decode(bytes.NewReader(raw))
+	if err != nil {
+		return nil, fmt.Errorf("解码图片失败: %w", err)
+	}
+
+	webpBytes, err := encodeWebPBytes(img, UploadWebPQuality, UploadWebPMethod)
+	if err != nil {
+		return nil, fmt.Errorf("转换 WebP 失败: %w", err)
+	}
+	out.WebPData = webpBytes
+	return out, nil
+}
+
+func gifFrameCount(raw []byte) int {
+	g, err := gif.DecodeAll(bytes.NewReader(raw))
+	if err != nil || g == nil {
+		return 0
+	}
+	return len(g.Image)
+}
+
+func encodeWebPBytes(img image.Image, quality float32, method int) ([]byte, error) {
+	var buf bytes.Buffer
+	if err := gowebp.Encode(&buf, img, &gowebp.Options{
+		Lossy:   true,
+		Quality: quality,
+		Method:  method,
+	}); err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+func normalizeImageDelivery(raw string) string {
+	if strings.ToLower(strings.TrimSpace(raw)) == ImageDeliveryOriginal {
+		return ImageDeliveryOriginal
+	}
+	return ImageDeliveryWebP
+}
+
+func imageContentType(ext string) string {
+	switch strings.ToLower(ext) {
+	case ".jpg", ".jpeg":
+		return "image/jpeg"
+	case ".png":
+		return "image/png"
+	case ".gif":
+		return "image/gif"
+	case ".webp":
+		return "image/webp"
+	default:
+		return "application/octet-stream"
+	}
+}
+
+// siblingUploadExts 同主文件名可能存在的伴生扩展名（删除时一并清理）
+func siblingUploadExts(ext string) []string {
+	ext = strings.ToLower(ext)
+	all := []string{".jpg", ".jpeg", ".png", ".gif", ".webp"}
+	out := make([]string, 0, len(all))
+	for _, e := range all {
+		if e == ext || (ext == ".jpg" && e == ".jpeg") || (ext == ".jpeg" && e == ".jpg") {
+			continue
+		}
+		out = append(out, e)
+	}
+	return out
+}