feat(storage): add dynamic storage config and migration

Move storage backend configuration from startup YAML to system_config-backed runtime configuration. Add local, S3-compatible, R2, MinIO, OSS, and WebDAV backend support.

Add a storage migration async task using the existing task dispatch framework. Migration target config is carried in task payload, and maintenance mode is derived from task execution state.

Split upload file management and storage operations, add the admin storage configuration tab, and update migrations and Swagger docs.

internal/apps/upload/file_server.go

@@ -12,7 +12,6 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"os"
 	"strconv"
 	"strings"
 
@@ -22,7 +21,6 @@ import (
 	"github.com/Rain-kl/Wavelet/internal/diskcache"
 	"github.com/Rain-kl/Wavelet/internal/logger"
 	"github.com/Rain-kl/Wavelet/internal/model"
-	"github.com/Rain-kl/Wavelet/internal/storage"
 	"github.com/Rain-kl/Wavelet/internal/util"
 	"github.com/gin-gonic/gin"
 	"gorm.io/gorm"
@@ -236,48 +234,21 @@ func normalizeImageQuality(quality string) string {
 
 // serveOriginal 原始文件的流式响应逻辑
 func serveOriginal(c *gin.Context, upload *model.Upload) {
-	if upload.StorageDriver == storageDriverLocal || (upload.StorageDriver == "" && !storage.IsEnabled()) {
-		c.File(upload.FilePath)
-		return
-	}
-
-	// Retrieve file from S3 (via CDN if configured)
-	obj, err := storage.GetObjectViaCache(c.Request.Context(), upload.FilePath)
+	obj, err := openStoredObject(c.Request.Context(), upload)
 	if err != nil {
 		c.AbortWithStatus(http.StatusNotFound)
 		return
 	}
-
-	// Cachefile
-	if obj.CachePath != "" {
-		c.File(obj.CachePath)
-		return
-	}
-
-	// Stream from CDN/S3
 	defer func() { _ = obj.Body.Close() }()
-
-	// Respond with the file content
 	c.DataFromReader(http.StatusOK, obj.ContentLength, obj.ContentType, obj.Body, nil)
 }
 
 // getOriginalFileBytes 获取原始文件所有字节
 func getOriginalFileBytes(ctx context.Context, upload *model.Upload) ([]byte, error) {
-	if upload.StorageDriver == storageDriverLocal || (upload.StorageDriver == "" && !storage.IsEnabled()) {
-		return os.ReadFile(upload.FilePath)
-	}
-
-	// Retrieve file from S3 (via CDN if configured)
-	obj, err := storage.GetObjectViaCache(ctx, upload.FilePath)
+	obj, err := openStoredObject(ctx, upload)
 	if err != nil {
 		return nil, err
 	}
-
-	// Cachefile
-	if obj.CachePath != "" {
-		return os.ReadFile(obj.CachePath)
-	}
-
 	defer func() { _ = obj.Body.Close() }()
 	return io.ReadAll(obj.Body)
 }