The blocked patterns for 'reboot' and 'shutdown' were too broad,
matching anywhere in the command string. This caused legitimate
Proxmox VM control commands like 'qm reboot 201' to be blocked
instead of requiring approval.
Fix by anchoring these patterns to only match bare system commands
(^reboot, ^shutdown, etc.) while allowing qm/pct variants through
the RequireApproval path.
Related to #1024