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/update.go

@@ -104,6 +104,10 @@ func (m Model) handleKey(k tea.KeyMsg) (tea.Model, tea.Cmd) {
 	if m.overlay != OverlayNone {
 		return m.handleOverlayKey(k)
 	}
+	if m.displayState() == StateClarification {
+		m.clarEnsureState()
+		return m.handleClarificationKey(k)
+	}
 	if m.editMode == ModeInsert {
 		return m.handleInsertKey(k)
 	}