Team UI indicators persist after force-deleting team files (zombie teammates)

Bug Description

When a team is created with teammates and the teammate processes are killed manually (Ctrl+C in tmux panes, then exit), the teammate UI indicators persist in the lead agent's session — showing spinning animations, teammate count, and a ticking time counter — even though no agents are actually running and no tokens are being consumed.

Steps to Reproduce

1. Create a team with TeamCreate and spawn 3 teammates via Task tool
2. While teammates are still running, manually kill them:

• Switch to each teammate's tmux pane
• Press Ctrl+C to interrupt the running agent
• Type exit to close the tmux pane

1. Return to the lead agent's session
2. Result: UI still shows "3 teammates" with spinning indicators, time counter ticking, but 0 tokens used
3. Attempting TeamDelete fails with "Cannot cleanup team with 3 active member(s)"
4. Even force-deleting files (rm -rf ~/.claude/teams/team-name ~/.claude/tasks/team-name) does not clear the UI indicators
5. Only restarting the Claude Code session clears the stale state

Expected Behavior

Either:

• The lead agent should detect that teammate tmux panes have been killed and clean up the in-memory state automatically (heartbeat/health check)
• TeamDelete should support a --force flag to clean up even when agents are listed as active but their processes are dead
• The UI should reconcile in-memory state against actual tmux pane status — if the pane no longer exists, clear the teammate indicator

Root Cause Analysis

The UI reads teammate state from in-memory AppState, not from the filesystem or tmux process status. When a teammate's tmux pane is killed externally (Ctrl+C + exit), the lead agent's AppState is never notified — the teammate is still listed as isActive: true in the team config, and the in-memory state retains the stale entry.

The TeamDelete tool refuses to operate if any members are listed as active in the config, creating a deadlock — the agents are dead but still "active" according to the config, so TeamDelete won't run and there's no way to clear the state without restarting the session.

Environment

• Claude Code version: latest (Feb 2026)
• OS: macOS (Darwin 25.1.0)
• Shell: zsh

Screenshot

The UI shows "3 teammates" with spinning indicators and time counter ticking, but no tokens are being consumed.