Refactor the currency management system to eliminate the redundant
`rate_to_aed` field and transition to a single-base model where all
rates are stored relative to the Iranian Rial (IRR).
Key changes:
- Removed `rate_to_aed` from `currencies` table via new migration.
- Updated `ExchangeRateService` to handle rates using a single
`currency_code` parameter instead of currency pairs.
- Refactored `UpdateExchangeRates` command to fetch rates from the
Exir.io API and support multiple currencies (AED, USD, EUR, CNY).
- Updated Filament resources (`CurrencyResource`,
`ExchangeRateHistoryResource`) and widgets to reflect the new
single-base architecture.
- Improved `PriceCalculatorService` to use the updated service
methodology for fetching the AED/IRR conversion rate.
- Localized console command output to Persian.
Introduce a mechanism to track and audit changes in exchange rates.
This includes:
- Creating `ExchangeRateHistory` model and migration to store rate changes.
- Implementing `ExchangeRateService` to encapsulate rate logic.
- Updating `UpdateExchangeRates` command to record history when rates change.
- Adding `ExchangeRateHistoryResource` to the Filament admin panel for monitoring.
