feat(data): add Polymarket prediction markets as a keyless vendor

Surface live, market-implied probabilities for forward-looking events (Fed
decisions, recession, elections, geopolitics, crypto) to the news analyst via a
new get_prediction_markets tool and a prediction_markets vendor category. Backed
by Polymarket's public Gamma API (no key). Results are filtered to open,
forward-looking markets (closed and past-dated events excluded), ranked by
traded volume, and rendered with implied probability, volume, resolution date,
and the recent move. External errors degrade to a clear unavailable message
rather than interrupting the analyst.

tests/test_polymarket.py

@@ -0,0 +1,129 @@
+"""Polymarket prediction-market vendor: forward-looking filtering, volume
+ranking, formatting, graceful degradation, and router integration.
+
+All API access is mocked, so these run without a network connection.
+"""
+import copy
+import unittest
+from unittest import mock
+
+import pytest
+import requests
+
+import tradingagents.dataflows.config as config_module
+import tradingagents.default_config as default_config
+from tradingagents.dataflows import interface, polymarket
+from tradingagents.dataflows.config import set_config
+
+
+def _market(question, prob, *, volume, end_date, closed=False, wk=None):
+    return {
+        "question": question,
+        "outcomes": '["Yes", "No"]',
+        "outcomePrices": f'["{prob}", "{round(1 - prob, 4)}"]',
+        "volumeNum": volume,
+        "endDate": end_date,
+        "closed": closed,
+        "oneWeekPriceChange": wk,
+    }
+
+
+# One event with a mix: a high-volume open market, a closed one, a past-dated
+# one, and a lower-volume open one. Far-future / far-past dates keep the test
+# independent of the real clock.
+_SEARCH = {
+    "events": [
+        {
+            "markets": [
+                _market("Open big?", 0.76, volume=5_000_000, end_date="2030-12-31T00:00:00Z", wk=-0.045),
+                _market("Resolved already?", 1.0, volume=9_000_000, end_date="2030-12-31T00:00:00Z", closed=True),
+                _market("Past event?", 0.5, volume=8_000_000, end_date="2020-01-01T00:00:00Z"),
+                _market("Open small?", 0.30, volume=1_000, end_date="2030-06-30T00:00:00Z"),
+            ]
+        }
+    ]
+}
+
+
+@pytest.mark.unit
+class PolymarketFilterTests(unittest.TestCase):
+    def test_closed_and_past_markets_are_excluded(self):
+        with mock.patch.object(polymarket, "_request", return_value=_SEARCH):
+            out = polymarket.get_prediction_markets("anything", limit=10)
+        self.assertIn("Open big?", out)
+        self.assertIn("Open small?", out)
+        self.assertNotIn("Resolved already?", out)  # closed
+        self.assertNotIn("Past event?", out)         # endDate in the past
+
+    def test_ranked_by_volume(self):
+        with mock.patch.object(polymarket, "_request", return_value=_SEARCH):
+            out = polymarket.get_prediction_markets("anything", limit=10)
+        self.assertLess(out.index("Open big?"), out.index("Open small?"))
+
+    def test_limit_caps_results(self):
+        with mock.patch.object(polymarket, "_request", return_value=_SEARCH):
+            out = polymarket.get_prediction_markets("anything", limit=1)
+        self.assertIn("Open big?", out)
+        self.assertNotIn("Open small?", out)
+
+
+@pytest.mark.unit
+class PolymarketFormatTests(unittest.TestCase):
+    def test_probability_volume_and_weekly_change_render(self):
+        with mock.patch.object(polymarket, "_request", return_value=_SEARCH):
+            out = polymarket.get_prediction_markets("anything", limit=10)
+        self.assertIn("Yes 76%", out)
+        self.assertIn("$5,000,000 volume", out)
+        self.assertIn("resolves 2030-12-31", out)
+        self.assertIn("1-week -4.5pp", out)  # -0.045 -> -4.5pp
+
+    def test_weekly_change_omitted_when_absent(self):
+        # "Open small?" has wk=None -> no 1-week clause on its line.
+        with mock.patch.object(polymarket, "_request", return_value=_SEARCH):
+            out = polymarket.get_prediction_markets("anything", limit=10)
+        small_line = next(ln for ln in out.splitlines() if "Open small?" in ln)
+        self.assertNotIn("1-week", small_line)
+
+    def test_no_matches_reports_clearly(self):
+        with mock.patch.object(polymarket, "_request", return_value={"events": []}):
+            out = polymarket.get_prediction_markets("obscure ticker", limit=6)
+        self.assertIn("No open prediction markets", out)
+
+
+@pytest.mark.unit
+class PolymarketResilienceTests(unittest.TestCase):
+    def test_network_error_degrades_gracefully(self):
+        # An external-service hiccup must not raise into the analyst.
+        with mock.patch.object(
+            polymarket, "_request", side_effect=requests.RequestException("boom")
+        ):
+            out = polymarket.get_prediction_markets("Fed rate cut")
+        self.assertIn("unavailable", out.lower())
+        self.assertIn("Fed rate cut", out)
+
+
+@pytest.mark.unit
+class PolymarketRoutingTests(unittest.TestCase):
+    def setUp(self):
+        config_module._config = copy.deepcopy(default_config.DEFAULT_CONFIG)
+
+    def tearDown(self):
+        config_module._config = copy.deepcopy(default_config.DEFAULT_CONFIG)
+
+    def test_category_routes_to_polymarket(self):
+        self.assertEqual(
+            interface.get_category_for_method("get_prediction_markets"),
+            "prediction_markets",
+        )
+        set_config({"data_vendors": {"prediction_markets": "polymarket"}})
+        with mock.patch.dict(
+            interface.VENDOR_METHODS,
+            {"get_prediction_markets": {"polymarket": lambda *a, **k: "POLY_OK"}},
+            clear=False,
+        ):
+            out = interface.route_to_vendor("get_prediction_markets", "fed", 5)
+        self.assertEqual(out, "POLY_OK")
+
+
+if __name__ == "__main__":
+    unittest.main()