feat(mcp): Steward's own backups: the runs, the next one, checking and making one (#5836)

list_backups, check_backup and make_backup are Settings → Backups for an
agent, admin only like the page. make_backup runs the page's job in the
background and is audited as "<user> via MCP". Restoring stays in the
browser. get_overview names a scheduled backup that failed, is two hours
past its slot, or has no bucket.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

steward/mcp/tools/__init__.py

@@ -12,9 +12,10 @@ each argument's empty value means, and what comes back.
 """
 from __future__ import annotations
 
-from . import alerts, anomalies, audit, automation, hosts, metrics, monitors, overview, session
+from . import alerts, anomalies, audit, automation, backups, hosts, metrics, monitors, overview, session
 
-_MODULES = (session, overview, hosts, monitors, alerts, anomalies, metrics, audit, automation)
+_MODULES = (session, overview, hosts, monitors, alerts, anomalies, metrics, audit, automation,
+            backups)
 
 
 def register_all(register_tool) -> None: