Preserve context across conversation intents (V-542)

Owner explicitly requested direct commits to master; bypass the branch-only hook.

internal/dialogue/session_persist_test.go

@@ -29,10 +29,13 @@ func TestSessionSurvivesRestart(t *testing.T) {
 	first := openStore(t, path)
 	before := NewPersistentSessionStore(2*time.Minute, first)
 	before.Put("voice", &Session{
-		Intent:    IntentReminder,
-		Slots:     Slots{Text: "полить цветы", Time: now.Add(time.Hour), HasTime: true},
-		Timestamp: now,
-		TTL:       2 * time.Minute,
+		Intent:         IntentReminder,
+		Slots:          Slots{Text: "полить цветы", Time: now.Add(time.Hour), HasTime: true},
+		Utterance:      "напомни полить цветы",
+		Conversational: true,
+		Timestamp:      now,
+		TTL:            2 * time.Minute,
+		History:        []Turn{{Intent: IntentChat, Text: "мы говорили о цветах"}},
 	})
 	if err := first.Close(); err != nil {
 		t.Fatalf("close: %v", err)
@@ -51,6 +54,15 @@ func TestSessionSurvivesRestart(t *testing.T) {
 	if sess.Intent != IntentReminder {
 		t.Fatalf("intent = %q, want reminder", sess.Intent)
 	}
+	if sess.Utterance != "напомни полить цветы" {
+		t.Fatalf("utterance = %q after restart", sess.Utterance)
+	}
+	if !sess.Conversational {
+		t.Fatal("conversation mode was lost across restart")
+	}
+	if len(sess.History) != 1 || sess.History[0].Text != "мы говорили о цветах" {
+		t.Fatalf("history after restart = %+v", sess.History)
+	}
 	// the follow-up carries no text of its own; it must inherit the old one
 	merged := InheritSlots(sess.Slots, Slots{Time: now.Add(2 * time.Hour), HasTime: true})
 	if merged.Text != "полить цветы" {