Release 1.21.0

1.21.0 (2026-09-14)

✨ Features

• storage: add rclone config model and validation helpers (9409f0f)
• storage: add RcloneProvider upload path (ba83b6b)
• storage: sftp config model and rclone-config builder (c353443)
• storage: sftp provider over rclone rcat (c70cde8)
• storage: stream backups into rclone rcat (b222b13)

🐛 Bug Fixes

• refactoring (d52c328)
• refactoring (f6e1a0d)
• refactoring (6d1d7c6)
• refactoring (9bb8303)
• storage: abort truncated rclone uploads and strengthen stderr test (ea356ed)
• storage: block virtual and non-viable rclone backends (31e55a7)
• storage: bound rclone timeouts, detect restore truncation, track sdd workspace (576c055)
• storage: reject line breaks in sftp host/username; drop unused import (012a984)
• tests (6e50718)
• tests (ee5ed81)

🔧 Chores

• update packages (24e3e30)