Two issues caused the rate import to fail with 1237 'Out of range
value for column rate' errors:
1. The rate column was decimal(12,4) — max ~100 million. Converted
IRR values for larger shipments exceed this. Migrate to
decimal(20,4) which handles up to ~100 trillion.
2. The fallback AED→IRR rate in config/ifnex.php was 455,000 (way
too high — should be ~14,000). Update to a realistic market rate.
Also improve the CurrencyResource helperText to remind users to
enter rates in Rials (not Tomans) and provide realistic examples
for AED, USD, and EUR.
477418b349