feat(tui-go): interactive clarification question view

Render stage clarification questions as an AskUserQuestion-style form:
header chip, prompt, selectable option chips, and a free-text custom slot.
Arrow/hjkl nav, space to select, e for custom, enter to submit. Submit
guards on all-answered and sends ClarificationResponse; the parked stage
re-runs with the answers in context.

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

@@ -132,11 +132,13 @@ func (m *Model) applyServer(msg protocol.ServerMessage) {
 		m.touch(msg.SessionID, "COMPLETED")
 		if s := m.session(msg.SessionID); s != nil {
 			s.Active = false
+			s.Clar = nil
 		}
 	case protocol.TypeSessionFailed:
 		m.touch(msg.SessionID, "FAILED")
 		if s := m.session(msg.SessionID); s != nil {
 			s.Active = false
+			s.Clar = nil
 		}
 	case protocol.TypeStageStarted:
 		if s := m.session(msg.SessionID); s != nil {
@@ -242,6 +244,8 @@ func (m *Model) applyServer(msg protocol.ServerMessage) {
 		}
 	case protocol.TypeApprovalRequired:
 		m.onApprovalRequired(msg)
+	case protocol.TypeClarification:
+		m.onClarificationRequired(msg)
 	case protocol.TypeApprovalResolved:
 		if s := m.session(msg.SessionID); s != nil {
 			s.Pending = nil
@@ -400,6 +404,26 @@ func (m *Model) onApprovalRequired(msg protocol.ServerMessage) {
 	}
 }
 
+func (m *Model) onClarificationRequired(msg protocol.ServerMessage) {
+	qs := make([]ClarQuestion, 0, len(msg.Questions))
+	for _, q := range msg.Questions {
+		qs = append(qs, ClarQuestion{
+			ID: q.ID, Prompt: q.Prompt, Header: q.Header,
+			Options: q.Options, MultiSelect: q.MultiSelect,
+		})
+	}
+	c := &Clarification{
+		RequestID: msg.RequestID, SessionID: msg.SessionID,
+		StageID: msg.StageID, Questions: qs,
+	}
+	if s := m.session(msg.SessionID); s != nil {
+		s.Clar = c
+	}
+	if msg.SessionID == m.selectedID {
+		m.clarInitState(len(qs))
+	}
+}
+
 func (m *Model) onSnapshot(msg protocol.ServerMessage) {
 	var pending *Approval
 	if len(msg.PendingAppr) > 0 {