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.
