v1.9.3 — a stopped MCP server exits within five seconds, even if its logout hangs

A correction to 1.9.2, from an independent review on 2026-09-15. 1.9.2 made the server log out when Claude Code
stops it: the first stop signal ignored further stop signals and ran the atexit logout. The logout had no time
limit. pyVmomi connects with httpConnectionTimeout=None, so a logout to a vCenter that stopped answering, or
one waiting on the SOAP connection lock a tool call held when the signal arrived, kept the server running and
deaf to every further stop signal until something sent SIGKILL. Before 1.9.2, SIGTERM at least ended it.

• The logout now runs on a worker thread and gets 5 seconds. If it has not finished, the server writes one line
  to stderr without blocking (a full pipe cannot hold the exit) and exits with 128 + signal anyway; vCenter or
  ESXi ends that session when it idles out.
• New test: the real server with stdin held open, an atexit callback that blocks for ten minutes, then SIGINT
  and SIGTERM. The server must exit within 15 seconds and say it gave up on the logout. It failed on 1.9.2.
• Correction to the 1.9.2 notes: "conversations against the lab left no session behind" was not measured for this
  server. It is now, on this code: a conversation that called list_all_datastores and storage_iscsi_status
  against vCenter 8.0.3 left no session behind.