feat(tui): token metrics aggregation, plan overlay, tool reasoning, clar dismissal

#295 — include narration_llm tokens in changes-panel aggregate count
#296 — execution plan overlay (Ctrl+P in-session)
#298 — surface reasoning/CoT on tool-call turns in output view
#265 — dismiss clarification modal when answered externally (session.resumed)

apps/tui-go/internal/app/update.go

@@ -287,6 +287,11 @@ func (m Model) handleNormalKey(k keyMsg) (tea.Model, tea.Cmd) {
 			m.diffScrollOffset = 0
 		}
 		return m, nil
+	case keyCtrlP:
+		if ds == StateInSession {
+			m.overlay = OverlayPlan
+		}
+		return m, nil
 	}
 	if k.Type != keyRunes {
 		return m, nil
@@ -855,6 +860,10 @@ func (m Model) handleOverlayKey(k keyMsg) (tea.Model, tea.Cmd) {
 		if runeIs(k, "H") {
 			m.overlay = OverlayNone
 		}
+	case OverlayPlan:
+		if k.Type == keyCtrlP || runeIs(k, "p") {
+			m.overlay = OverlayNone
+		}
 	case OverlayIdeas:
 		switch {
 		case k.Type == keyUp || runeIs(k, "k"):