feat(market): verified market-data snapshot to ground numeric claims

The market analyst could confabulate exact figures — citing a Bollinger
band or a "historically validated bounce" the data doesn't support (#830).
Add a deterministic get_verified_market_snapshot tool (latest OHLCV row,
common indicators, recent closes) the analyst must consult and treat as
the source of truth for any exact price/indicator claim, and instruct it
not to assert historical validation or support bounces without tool-backed
dates and prices.

#830

tradingagents/agents/utils/market_data_validation_tools.py

@@ -0,0 +1,23 @@
+from typing import Annotated
+
+from langchain_core.tools import tool
+
+from tradingagents.dataflows.market_data_validator import build_verified_market_snapshot
+
+
+@tool
+def get_verified_market_snapshot(
+    symbol: Annotated[str, "ticker symbol of the company"],
+    curr_date: Annotated[str, "the current trading date, YYYY-mm-dd"],
+    look_back_days: Annotated[
+        int, "number of recent trading rows to include for sanity-checking"
+    ] = 30,
+) -> str:
+    """Deterministic verification snapshot for exact market-data claims.
+
+    Returns the latest OHLCV row on or before curr_date, common technical
+    indicators, and recent closes. Call this before making exact claims about
+    price levels, Bollinger bands, RSI, MACD, moving averages, support /
+    resistance, or historical comparisons, and treat it as the source of truth.
+    """
+    return build_verified_market_snapshot(symbol, curr_date, look_back_days)