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/server.go

@@ -136,8 +136,12 @@ func (m *Model) applyServer(msg protocol.ServerMessage) {
 		if s := m.session(msg.SessionID); s != nil {
 			s.Status = "ACTIVE"
 			s.clearApprovals()
+			s.Clar = nil
 			s.LastEventAt = nowMillis()
 		}
+		if msg.SessionID == m.selectedID {
+			m.clarResetState()
+		}
 	case protocol.TypeSessionCompleted:
 		m.touch(msg.SessionID, "COMPLETED")
 		if s := m.session(msg.SessionID); s != nil {
@@ -190,6 +194,7 @@ func (m *Model) applyServer(msg protocol.ServerMessage) {
 			}
 		}
 	case protocol.TypeInferenceStarted:
+		m.lastReasoning = ""
 		if s := m.session(msg.SessionID); s != nil {
 			s.Active = true
 			s.addEvent(nowMillis(), "InferenceStarted", msg.StageID)
@@ -209,6 +214,7 @@ func (m *Model) applyServer(msg protocol.ServerMessage) {
 			// row (revealed via the palette). Skipped when the model emits no separate channel.
 			if strings.TrimSpace(msg.Reasoning) != "" {
 				m.appendRouter(msg.SessionID, RouterEntry{Role: "thinking", Content: msg.Reasoning})
+				m.lastReasoning = msg.Reasoning
 			}
 		}
 	case protocol.TypeInferenceTimeout:
@@ -249,7 +255,7 @@ func (m *Model) applyServer(msg protocol.ServerMessage) {
 			// existing collapsed diff row (^x opens the full diff).
 			path, add, del := diffSummary(*msg.Diff)
 			m.appendAction(msg.SessionID, "✎", "wrote "+path+countSuffix(add, del))
-			m.appendRouter(msg.SessionID, RouterEntry{Role: "tool", Content: *msg.Diff})
+			m.appendRouter(msg.SessionID, RouterEntry{Role: "tool", Content: *msg.Diff, Reasoning: m.lastReasoning})
 		} else {
 			label := msg.ToolName
 			// Prefer the actual call args (path=…, command="…") over the affected-entities