fix(conversation): topic chips after warmup + English chip copy

- Buffer topic_suggestions until chat UI attaches (uiOwner + callback); replay on attach
- build_topic_chips respects user language for label/text; router passes user_language

Co-authored-by: Cursor <cursoragent@cursor.com>

api/tests/test_interview_turn_plan.py

@@ -286,3 +286,13 @@ def test_plan_follow_when_no_empty_slots():
     )
     assert p.mode == "follow_user_only"
     assert p.low_information_reply is True
+
+
+def test_build_topic_chips_english_uses_slot_name_map_en():
+    from app.agents.chat.prompts_conversation import build_topic_chips
+
+    chips = build_topic_chips("childhood", ["place"], max_chips=2, language="en")
+    assert len(chips) >= 1
+    place_chip = next(c for c in chips if c["id"] == "place")
+    assert place_chip["label"] == "where you grew up"
+    assert place_chip["text"].startswith("I'd like to talk about")