feat(data): add FRED macro indicators as an optional vendor

Surface Federal Reserve Economic Data (rates, inflation, labor, growth) to the
news analyst via a new get_macro_indicators tool and a macro_data vendor
category. Friendly aliases (cpi, unemployment, fed_funds_rate, 10y_treasury,
yield_curve, ...) map to FRED series IDs; raw series IDs are accepted too. The
report gives the latest value, change over the window, and a recent observation
table. Windowing is lookahead-safe (observation_end = curr_date), missing values
are skipped, and a missing FRED_API_KEY surfaces as a clear not-configured
condition through the vendor router rather than a crash.

tradingagents/agents/utils/macro_data_tools.py

@@ -0,0 +1,36 @@
+from typing import Annotated
+
+from langchain_core.tools import tool
+
+from tradingagents.dataflows.interface import route_to_vendor
+
+
+@tool
+def get_macro_indicators(
+    indicator: Annotated[
+        str,
+        "Macro indicator: a friendly alias such as 'cpi', 'core_pce', "
+        "'unemployment', 'fed_funds_rate', '10y_treasury', 'yield_curve', "
+        "'real_gdp', 'vix', or a raw FRED series ID such as 'CPIAUCSL'.",
+    ],
+    curr_date: Annotated[str, "Current date in yyyy-mm-dd format; the end of the window"],
+    look_back_days: Annotated[
+        int | None, "Trailing window length in days; omit for a 1-year window"
+    ] = None,
+) -> str:
+    """
+    Retrieve a macroeconomic indicator time series from FRED (Federal Reserve
+    Economic Data): policy rates, Treasury yields, inflation, labor, and growth.
+    Returns the series title, units, frequency, the latest value, the change
+    over the window, and a recent observation table. Uses the configured
+    macro_data vendor.
+
+    Args:
+        indicator (str): Friendly alias or raw FRED series ID
+        curr_date (str): Current date in yyyy-mm-dd format
+        look_back_days (int): Trailing window length; omit for a 1-year window
+
+    Returns:
+        str: A formatted markdown report of the macro series
+    """
+    return route_to_vendor("get_macro_indicators", indicator, curr_date, look_back_days)