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.

tradingagents/agents/utils/agent_utils.py

@@ -26,6 +26,9 @@ from tradingagents.agents.utils.news_data_tools import (
 from tradingagents.agents.utils.macro_data_tools import (
     get_macro_indicators
 )
+from tradingagents.agents.utils.prediction_markets_tools import (
+    get_prediction_markets
+)
 from tradingagents.agents.utils.market_data_validation_tools import (
     get_verified_market_snapshot
 )

tradingagents/agents/utils/prediction_markets_tools.py

@@ -0,0 +1,31 @@
+from typing import Annotated
+
+from langchain_core.tools import tool
+
+from tradingagents.dataflows.interface import route_to_vendor
+
+
+@tool
+def get_prediction_markets(
+    topic: Annotated[
+        str,
+        "Event topic/keyword, e.g. 'Fed rate cut', 'recession 2026', "
+        "'US election', or a sector/company event.",
+    ],
+    limit: Annotated[int | None, "Max markets to return; omit for a default of 6"] = None,
+) -> str:
+    """
+    Retrieve live, market-implied probabilities for forward-looking events from
+    prediction markets (Polymarket): Fed decisions, recession, elections,
+    geopolitics, crypto. Returns the most-traded open markets matching the
+    topic, each with its implied probability, traded volume, resolution date,
+    and recent move. Uses the configured prediction_markets vendor.
+
+    Args:
+        topic (str): Event keyword(s) to search
+        limit (int): Max markets to return; omit for a default of 6
+
+    Returns:
+        str: A formatted markdown report of matching prediction markets
+    """
+    return route_to_vendor("get_prediction_markets", topic, limit)