feat(sv): Backups card — offsite DR status (Core-4 -> Farm) + /api/backups (2.6.0)

migration 026 backup_runs; POST ingest (owner) from offsite-backup.sh, GET for the
Sacred Valley card showing last run, per-guest sizes, Farm free, schedule.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "void-server",
-  "version": "2.5.2",
+  "version": "2.6.0",
   "type": "module",
   "private": true,
   "scripts": {