Remote Control: stale/offline environments can't be removed from the machine/environment picker

Environment: Claude Code 2.1.280 / 2.1.299 on Linux (Oracle VPS, aarch64), viewed from the Claude iOS app and the desktop app

What happened:
I run claude remote-control in tmux on a VPS. Over time I ran it from several directories (/root/bot, /home/claudebot/ClaudeBot, /root/X). Later I renamed /root/X → /root/NewAPI. Now only two remote-control processes run (/root/NewAPI and /home/claudebot/Claude-Bot).

However, the environment picker (iOS "Select environment" and desktop "Search computers") still lists all old entries:

• bot, ClaudeBot (shown twice on iOS) — offline
• X — still shown as online with no sessions, even though no process on the host has that cwd and the directory no longer exists
• The iOS "new session" sheet still defaults to the deleted /root/X directory

Expected:

• A way to remove/forget offline environments (from the app or via a CLI command)
• Environments whose process was killed should go offline after the heartbeat times out
• The default directory should not point to a path that no longer exists

Steps to reproduce:

1. Run claude remote-control in dir A, then kill the process (e.g. kill the tmux session)
2. Rename dir A → B, start claude remote-control in B
3. The picker shows both A (stale, sometimes still "online") and B, and A can't be deleted