Reconcile tmux sessions after daemon restart without duplicate hosts #211

Goal

Discover and reattach valid managed tmux sessions after restart while cleaning only provably stale ownership records.

Scope

• Preserve managed tmux sessions across expected process and network interruptions.
• Never duplicate a session, replay a control action, or silently discard a pending approval.

Acceptance

• Discover and reattach valid managed tmux sessions after restart while cleaning only provably stale ownership records.
• Cover restart, disconnect, timeout, and duplicate-message paths.
• Export explicit recovery state to the fleet API.

Verification

• go test -race ./internal/daemon ./internal/tmux

Dependencies

#210