fix: return error on size mismatch in ReadNeedleMeta for consistency (#7687)

* fix: return error on size mismatch in ReadNeedleMeta for consistency

When ReadNeedleMeta encounters a size mismatch at offset >= MaxPossibleVolumeSize,
it previously just continued without returning an error, potentially using wrong data.

This fix makes ReadNeedleMeta consistent with ReadBytes (needle_read.go), which
properly returns an error in both cases:
- ErrorSizeMismatch when offset < MaxPossibleVolumeSize (to trigger retry at offset+32GB)
- A descriptive error when offset >= MaxPossibleVolumeSize (after retry failed)

Fixes #7673

* refactor: use more accurate error message for size mismatch

weed/storage/needle/needle_read_page.go

@@ -55,6 +55,7 @@ func (n *Needle) ReadNeedleMeta(r backend.BackendStorageFile, offset int64, size
 		if OffsetSize == 4 && offset < int64(MaxPossibleVolumeSize) {
 			return ErrorSizeMismatch
 		}
+		return fmt.Errorf("size mismatch for entry at offset %d: found id %x size %d, expected size %d", offset, n.Id, n.Size, size)
 	}
 	n.DataSize = util.BytesToUint32(bytes[NeedleHeaderSize : NeedleHeaderSize+DataSizeSize])
 	startOffset := offset + NeedleHeaderSize