fix(analysts): align the news prompt with the get_news tool signature

- prompt advertised get_news(query, ...) but the tool takes a ticker, so the
  model hallucinated free-text query calls
- advertise get_news(ticker, start_date, end_date) #1116

tests/test_news_analyst_prompt.py

@@ -0,0 +1,25 @@
+"""Guard the news analyst prompt against tool-signature drift (#1116).
+
+The prompt used to advertise ``get_news(query, ...)`` while the tool takes a
+``ticker``, tricking the LLM into hallucinating free-text query calls.
+"""
+import inspect
+
+import pytest
+
+import tradingagents.agents.analysts.news_analyst as na
+from tradingagents.agents.utils.news_data_tools import get_news
+
+
+@pytest.mark.unit
+def test_get_news_takes_ticker_not_query():
+    arg_names = set(get_news.args.keys())
+    assert "ticker" in arg_names
+    assert "query" not in arg_names
+
+
+@pytest.mark.unit
+def test_news_prompt_matches_get_news_signature():
+    src = inspect.getsource(na)
+    assert "get_news(ticker, start_date, end_date)" in src
+    assert "get_news(query" not in src