Removing a session from history doesn't terminate its process — orphaned `claude` processes accumulate (esp. Remote-SSH)

Environment

• Claude Code VS Code extension v2.1.162 (linux-arm64)
• VS Code Remote-SSH (extension host + sessions run on the remote Linux server; client on another machine)
• Conversation hosted as a docked view (sidebar/panel), not editor tabs

Summary

There is no user-facing command to end/terminate a session, and removing a session from the history list (trash icon) deletes only the session record — it never signals the underlying claude process. Under Remote-SSH the processes run server-side and survive client disconnects, so they accumulate indefinitely until the host reboots or they're killed by hand.

Evidence

A session is three decoupled artifacts:

1. the claude native-binary process,
2. a registry file ~/.claude/sessions/<pid>.json (pid → sessionId → cwd),
3. a transcript ~/.claude/projects/<proj>/<sessionId>.jsonl (persists by design).

Findings on one host:

• The extension contributes 22 commands; none of them stop / end / exit / kill / close a session's process. Closest are New Conversation and Reopen Closed Session.
• 10 live claude processes were running (~3 GB combined RSS). The registry mapped 1:1 to live PIDs, and 5 of them had been idle ~14 h with zero transcript writes — clearly orphaned. (40 transcripts on disk vs. 10 live sessions.)
• The process is the only thing holding the resources: kill -TERM <pid> exits each one cleanly, and on graceful exit the process self-removes its ~/.claude/sessions/<pid>.json. So the registry is process-lifecycle-managed — the UI simply never sends the terminate signal. Killing the 5 stale PIDs dropped RAM held by sessions from ~3.0 GB to ~1.6 GB.

Impact

A memory/CPU leak that is invisible in the UI. Worst under Remote-SSH, where session children run on the server and outlive client disconnects (laptop sleep, tunnel drop, window close); on a shared host they compete with other workloads.

Repro

1. Open the extension over Remote-SSH as a docked view.
2. Start several conversations (or reload the window so sessions are restored).
3. Remove old ones via the history trash icon, and/or disconnect the client.
4. On the server: ps aux | grep native-binary/claude → the old processes are still running; ~/.claude/sessions/ still holds their <pid>.json.

Expected

Ending a session (or removing it from history while it's still live) terminates its process — or there is a visible "End session" action, or history-trash prompts to terminate a still-running session.

Actual

Nothing in the UI terminates the process; it persists until reboot or a manual kill.

Suggested fixes (any one)

• Add an "End session" command + button that SIGTERMs the child.
• Make history-trash terminate the process when it's still live (or prompt).
• Make the remote server's idle-shutdown actually reap detached session children.