Cursor Agent7/1/2026, 11:03:28 PM

Phase 3 (part 2) of the Bun-native migration. Adds src/utils/subprocess.ts
(spawnStreamingSubprocess + subscribeLines line reader) and migrates the
streaming consumers off node:child_process and node:readline:

- sessionBackup/command.ts: tar/preview capture via Bun.spawn, exit-127
  contract for missing executables preserved
- coworkRuntime/libreOffice.ts: managed soffice probe with SIGKILL timeout
  race and a 4 MiB output cap (previously unbounded)
- webDesktopService.ts: workspace server monitor consumes web-stream line
  subscriptions; graceful SIGTERM-then-SIGKILL escalation kept

Co-authored-by: Max Weinbach <mweinbach@users.noreply.github.com>

Parentd4b21df