feat(ai_news): telegram includes article mapping stats line

stock-lab/tests/test_ai_news_telegram.py

@@ -53,3 +53,27 @@ def test_build_message_empty_lists():
     # 빈 리스트라도 헤더는 있어야 함
     assert "호재 Top" in msg
     assert "악재 Top" in msg
+
+
+def test_build_message_includes_mapping_line():
+    msg = tg.build_message(
+        asof="2026-05-14",
+        top_pos=[_row("005930", 8.5, "HBM 호재")],
+        top_neg=[],
+        tokens_input=1000, tokens_output=200,
+        mapping={"total_articles": 35, "matched_pairs": 50, "hit_tickers": 42},
+    )
+    assert "매핑" in msg
+    assert "42" in msg
+    assert "50" in msg
+    assert "35" in msg
+
+
+def test_build_message_without_mapping_omits_line():
+    msg = tg.build_message(
+        asof="2026-05-14",
+        top_pos=[],
+        top_neg=[],
+        tokens_input=1000, tokens_output=200,
+    )
+    assert "매핑" not in msg