chore: perauset customer project

sql/0019-exchange-rates.sql

@@ -0,0 +1,12 @@
+-- Exchange rates table for daily currency conversion
+CREATE TABLE app.exchange_rate (
+  rate_id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  base_currency TEXT NOT NULL DEFAULT 'EGP',
+  target_currency TEXT NOT NULL,
+  rate NUMERIC(12,6) NOT NULL,
+  fetched_at DATE NOT NULL,
+  created_at TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE UNIQUE INDEX idx_exchange_rate_unique ON app.exchange_rate(base_currency, target_currency, fetched_at);
+CREATE INDEX idx_exchange_rate_date ON app.exchange_rate(fetched_at DESC);