Maayan via Elementary: Fix: Convert historical_orders amounts from cents to dollars

[joostboon]

Problem\n\nThe historical_orders model was outputting monetary amounts in cents while real_time_orders outputs them in dollars. Since the orders model unions both via UNION ALL, this created a ~100× mismatch in the amount column for historical records.\n\nThis propagated through the pipeline:\nhistorical_orders → orders → customer_conversions → attribution_touches → cpa_and_roas\n\n...causing the RETURN_ON_ADVERTISING_SPEND anomaly test to fail with inflated ROAS values (incident has been failing for 69 consecutive runs).\n\n## Fix\n\n- historical_orders.sql: Apply the cents_to_dollars macro to all monetary columns, matching the pattern already used in real_time_orders.sql\n- real_time_orders.sql: Add a clarifying comment that amounts are in dollars (no logic changes)\n\n## Impact\n\nThis fix will normalize all monetary values to dollars across both order sources, resolving the ROAS anomaly on cpa_and_roas.

Created by: maayan+172@elementary-data.com