refactor(api): unify error handling and split upload/oauth god modules

Replace c.JSON(200, response.Err) and middleware gin.H bypasses with
response.Abort* helpers so errors flow through Gin Error chain and
ErrorHandlerMiddleware for OTel trace correlation.

Split oauth/sources.go into domain-focused files and decompose upload
into handler/filesrv/stats/task/cache/storage/util subpackages with a
root facade preserving existing import paths.

internal/apps/upload/task/tasks.go

@@ -0,0 +1,184 @@
+// Copyright 2025 linux.do
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package task
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+	"sync"
+
+	"github.com/Rain-kl/Wavelet/internal/apps/upload/filesrv"
+	"github.com/Rain-kl/Wavelet/internal/apps/upload/shared"
+	"github.com/Rain-kl/Wavelet/internal/db"
+	"github.com/Rain-kl/Wavelet/internal/model"
+	"github.com/Rain-kl/Wavelet/internal/task"
+)
+
+const (
+	// WarmImageCacheTask 图片压缩缓存预热任务标识
+	WarmImageCacheTask = "upload:warm_image_cache"
+	// TaskTypeWarmImageCache 图片压缩缓存预热管理类型
+	TaskTypeWarmImageCache = "warm_image_cache"
+)
+
+var warmImageCacheMu sync.Mutex
+
+// WarmImageCacheMeta represents the image cache warmup task metadata.
+var WarmImageCacheMeta = task.TaskMeta{
+	Type:         TaskTypeWarmImageCache,
+	AsynqTask:    WarmImageCacheTask,
+	Name:         "预热图片压缩缓存",
+	Description:  "串行将文件管理中的图片转换为指定质量的 WebP 并写入永久缓存",
+	SupportsTime: false,
+	MaxRetry:     task.DefaultMaxRetry,
+	Queue:        task.QueueDefault,
+	Retryable:    true,
+	Params: []task.TaskParam{
+		{
+			Name:        "quality",
+			Label:       "图片质量",
+			Type:        "string",
+			Required:    true,
+			Placeholder: "low / medium / high",
+			Description: "WebP 压缩质量，仅支持 low、medium、high",
+		},
+	},
+}
+
+// WarmImageCachePayload is the image cache warmup task payload.
+type WarmImageCachePayload struct {
+	Quality string `json:"quality"`
+}
+
+// WarmImageCacheHandler serially warms compressed image cache entries.
+type WarmImageCacheHandler struct{}
+
+// ValidatePayload validates and normalizes image cache warmup parameters.
+func (h *WarmImageCacheHandler) ValidatePayload(payload []byte) ([]byte, error) {
+	if len(payload) == 0 {
+		return nil, errors.New(shared.ErrImageCacheWarmupPayloadRequired)
+	}
+
+	var req WarmImageCachePayload
+	if err := json.Unmarshal(payload, &req); err != nil {
+		return nil, fmt.Errorf(shared.ErrInvalidImageCacheWarmupPayload, err)
+	}
+
+	req.Quality = strings.ToLower(strings.TrimSpace(req.Quality))
+	if req.Quality != shared.ImageQualityLow &&
+		req.Quality != shared.ImageQualityMedium &&
+		req.Quality != shared.ImageQualityHigh {
+		return nil, errors.New(shared.ErrInvalidImageCacheWarmupQuality)
+	}
+
+	return json.Marshal(req)
+}
+
+// Execute serially converts all managed images to WebP cache entries.
+func (h *WarmImageCacheHandler) Execute(ctx context.Context, payload []byte) (*task.TaskResult, error) {
+	normalizedPayload, err := h.ValidatePayload(payload)
+	if err != nil {
+		task.AppendLog(ctx, "图片缓存预热参数无效: %v", err)
+		return nil, err
+	}
+
+	var req WarmImageCachePayload
+	if err := json.Unmarshal(normalizedPayload, &req); err != nil {
+		return nil, fmt.Errorf(shared.ErrParseImageCacheWarmupPayload, err)
+	}
+
+	task.AppendLog(ctx, "等待获取图片缓存预热执行锁，质量: %s", req.Quality)
+	warmImageCacheMu.Lock()
+	defer warmImageCacheMu.Unlock()
+
+	const (
+		batchSize      = 50
+		maxFailureLogs = 5
+	)
+	var lastID uint64
+	var totalProcessed int
+	var totalCached int
+	var totalGenerated int
+	var totalFailed int
+
+	task.AppendLog(ctx, "开始串行预热图片压缩缓存，质量: %s，每批: %d", req.Quality, batchSize)
+
+	for {
+		if err := ctx.Err(); err != nil {
+			return nil, fmt.Errorf("image cache warmup canceled: %w", err)
+		}
+
+		var uploads []model.Upload
+		if err := db.DB(ctx).
+			Where("id > ? AND status != ? AND (LOWER(mime_type) LIKE ? OR LOWER(extension) IN ?)",
+				lastID,
+				model.UploadStatusDeleted,
+				"image/%",
+				[]string{"jpg", "jpeg", "png", "webp", "gif"},
+			).
+			Order("id ASC").
+			Limit(batchSize).
+			Find(&uploads).Error; err != nil {
+			task.AppendLog(ctx, "查询图片上传记录失败: %v", err)
+			return nil, fmt.Errorf(shared.ErrQueryImagesForCacheWarmup, err)
+		}
+
+		if len(uploads) == 0 {
+			break
+		}
+
+		batchGenerated := 0
+		batchCached := 0
+		batchFailed := 0
+		for i := range uploads {
+			if err := ctx.Err(); err != nil {
+				return nil, fmt.Errorf("image cache warmup canceled: %w", err)
+			}
+
+			upload := &uploads[i]
+			totalProcessed++
+			lastID = upload.ID
+
+			_, cacheHit, err := filesrv.EnsureCompressedImageCache(ctx, upload, req.Quality)
+			if err != nil {
+				totalFailed++
+				batchFailed++
+				if totalFailed <= maxFailureLogs {
+					task.AppendLog(ctx, "图片处理失败 [ID:%d]: %v", upload.ID, err)
+				}
+				continue
+			}
+			if cacheHit {
+				totalCached++
+				batchCached++
+				continue
+			}
+			totalGenerated++
+			batchGenerated++
+		}
+
+		task.AppendLog(
+			ctx,
+			"批次完成，末尾 ID: %d，生成: %d，命中: %d，失败: %d",
+			lastID,
+			batchGenerated,
+			batchCached,
+			batchFailed,
+		)
+	}
+
+	msg := fmt.Sprintf(
+		"图片缓存预热完成，共处理 %d 张，生成 %d 张，命中 %d 张，失败 %d 张",
+		totalProcessed,
+		totalGenerated,
+		totalCached,
+		totalFailed,
+	)
+	task.AppendLog(ctx, "%s", msg)
+	return &task.TaskResult{Message: msg}, nil
+}