WP-30/31/32: backup targets, strategies and execution

SMB (smbclient) and FTP/FTPS (curl with netrc) targets with encrypted
credentials and connection test; strategies with cron schedule, retention,
optional openssl AES-256 encryption; sources: PVC hostpath tar, pg_dumpall
in the Postgres pod, namespace manifests, host directory. Backup job
collects, encrypts, uploads, verifies size, records sha256 and applies
retention on the target; scheduler starts due strategies. Backups page
with target/strategy forms, run now and history. Restore guide in docs.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

backend/crates/application/src/test_fakes.rs

@@ -748,7 +748,7 @@ impl BackupRecordRepository for MemRecords {
             .filter(|r| r.strategy_id == strategy_id)
             .cloned()
             .collect();
-        v.sort_by(|a, b| b.created_at.cmp(&a.created_at));
+        v.sort_by_key(|r| std::cmp::Reverse(r.created_at));
         v.truncate(limit as usize);
         Ok(v)
     }