Add live terminal output views for each worker lane in the macOS cockpit:

Backend:
- Add PtyLogSubscriber infrastructure to CodeCockpitRuntime for real-time
  log chunk streaming to subscribers
- Add readWorkerPtySnapshot() for polling current terminal state
- Add code.worker.pty.snapshot, code.worker.pty.subscribe, and
  code.worker.pty.unsubscribe gateway endpoints

macOS app:
- Add CockpitTerminalLane SwiftUI view with ANSI-stripped scrolling output
- Add CockpitTerminalStore with polling-based live updates (1.5s interval)
- Add CockpitTerminalLanesSection with 2-column grid layout
- Wire terminal stores lifecycle into CockpitStore.reconcileTerminalStores()
- Add CockpitPtySnapshot and CockpitPtySubscription data models
- Add GatewayConnection methods for PTY snapshot and subscription

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>