This PR refactors the streaming subsystem to support direct download of fully contained sstables. Instead of streaming these files, they are downloaded and attached directly to their corresponding tables. This approach reduces overhead, simplifies logic, and improves efficiency. Expected node scope restore performance improvement: ~4 times faster in best case scenario when all sstables are fully contained.
1. Add storage options field to sstable Introduce a data member to store storage options, enabling distinction between local and object storage types.
2. Add method to create component source Extend the storage interface with a public method to create a data_source for any sstable component.
3. Inline streamer instance creation Remove make_sstable_streamer and inline its usage to allow different sets of arguments at call sites.
4. Skip streaming empty sstable sets Avoid unnecessary streaming calls when the sstable set is empty.
5. Enable direct download of contained sstables Replace streaming of fully contained sstables with direct download, attaching them to their corresponding table.
Fixes: https://scylladb.atlassian.net/browse/SCYLLADB-200
Refs: https://github.com/scylladb/scylladb/issues/23908
No need to backport as this code targets 2026.2 release (for tablet-aware restore)
Closesscylladb/scylladb#26834
* github.com:scylladb/scylladb:
tests: reuse test_backup_broken_streaming
streaming: enable direct download of contained sstables
storage: add method to create component source
streaming: keep sharded database reference on tablet_sstable_streamer
streaming: skip streaming empty sstable sets
streaming: inline streamer instance creation
tests: fix incorrect backup/restore test flow
1796997ace