Implement RPC skeleton for regular/EC volumes scrubbing. (#8187)

* Implement RPC skeleton for regular/EC volumes scrubbing.

See https://github.com/seaweedfs/seaweedfs/issues/8018 for details.

* Minor proto improvements for `ScrubVolume()`, `ScrubEcVolume()`:

  - Add fields for scrubbing details in `ScrubVolumeResponse` and `ScrubEcVolumeResponse`,
    instead of reporting these through RPC errors.
  - Return a list of broken shards when scrubbing EC volumes, via `EcShardInfo'.

weed/storage/disk_location.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
@@ -395,6 +396,38 @@ func (l *DiskLocation) FindVolume(vid needle.VolumeId) (*Volume, bool) {
 	return v, ok
 }
 
+// Returns all regular volume IDs stored at this location.
+func (l *DiskLocation) VolumeIds() []needle.VolumeId {
+	l.volumesLock.RLock()
+	defer l.volumesLock.RUnlock()
+
+	vids := make([]needle.VolumeId, len(l.volumes))
+	i := 0
+	for vid := range l.volumes {
+		vids[i] = vid
+		i++
+	}
+
+	slices.Sort(vids)
+	return vids
+}
+
+// Returns all EC volume IDs stored at this location.
+func (l *DiskLocation) EcVolumeIds() []needle.VolumeId {
+	l.ecVolumesLock.RLock()
+	defer l.ecVolumesLock.RUnlock()
+
+	vids := make([]needle.VolumeId, len(l.ecVolumes))
+	i := 0
+	for vid := range l.ecVolumes {
+		vids[i] = vid
+		i++
+	}
+
+	slices.Sort(vids)
+	return vids
+}
+
 func (l *DiskLocation) VolumesLen() int {
 	l.volumesLock.RLock()
 	defer l.volumesLock.RUnlock()