Add boot session uuid to proto event logs

[mlw]

Fixes #211

[
  {
   "event_time": "2025-01-29T15:45:09.171590Z",
   "processed_time": "2025-01-29T15:45:09.171590Z",
   "boot_session_uuid": "aa3fade9b04741bd972df8ab4f003e96",
   "disk": { ... }
  },
  {
   "event_time": "2025-01-29T15:45:12.305985602Z",
   "processed_time": "2025-01-29T15:45:12.319282Z",
   "boot_session_uuid": "aa3fade9b04741bd972df8ab4f003e96",
   "execution": { ... }
  },
  ...
]