## Summary
- Add Bitpanda as a new exchange provider using a single API key
(`X-Api-Key` header) to sync crypto and fiat wallet balances
- Follow the same architecture as Binance: provider string on
`banking_connections`, dedicated API client, balance sync service,
controller, form request, job wiring, factory state, route, and frontend
dialog
- Convert crypto wallet balances to the user's target currency via
`CurrencyConversionService`; fiat wallets are added directly or
converted if in a different currency
- Bitpanda appears in all countries in the connect dialog (same as
Binance)
- 18 new tests covering controller validation, balance sync scenarios,
sync job delegation, expiry handling, and email suppression
fe76c2e43d