Tell him when an expired clarify question is dropped

Vikunja #382. A parked clarifying question past its TTL was discarded
silently on read; now she says the old request is gone and the newly
spoken words are still routed as a fresh utterance.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CGeSZxh1DCtRxmFVSYVGvJ

internal/dialogue/clarify.go

@@ -100,6 +100,21 @@ func (s *ClarifyStore) Get(id string, now time.Time) *PendingQuestion {
 	return q
 }
 
+// TakeExpired reports whether a question was parked here but its TTL ran out,
+// and drops it. Get drops such a question silently, which leaves the user
+// thinking his request is still alive — the caller uses this to tell him it is
+// gone before treating his words as a fresh utterance.
+func (s *ClarifyStore) TakeExpired(id string, now time.Time) bool {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	q, ok := s.questions[id]
+	if !ok || !q.IsExpired(now) {
+		return false
+	}
+	delete(s.questions, id)
+	return true
+}
+
 func (s *ClarifyStore) Delete(id string) {
 	s.mu.Lock()
 	delete(s.questions, id)