No unknowns. This feature builds directly on the existing 013-keyboard-navigation infrastructure.
Decision: Use ⏸ (U+23F8, double vertical bar) as the pause icon. Rationale: Universally recognized pause symbol. Available in most terminal fonts.
Decision: Overlay rendering (replace session list temporarily with help text). Rationale: Simpler than floating panes, fits within existing render function. Any key dismisses. Alternative: Notification-based (too small), floating pane (overkill).
Decision: Add paused: bool to Session struct (already serializable via serde).
Rationale: Session is already synced between instances via broadcast_state. The paused field will be included automatically.