Check whether a one-click backend update can start

Runs the named preflight checks for the managed macOS update supervisor, each with a fix hint. Results are cached for 30 seconds. Requires owner role.

curl -X GET "https://example.com/v1/system/update/preflight"

{  "checked_at": 0,  "checks": [    {      "detail": "string",      "fix": "string",      "id": "string",      "label": "string",      "status": "pass"    }  ],  "ready": true}