## Problem
`PHP-LARAVEL-2M` (High, escalating, 38 events) — `RuntimeException:
Failed to fetch currency rates for xxx on 2025-12-31: HTTP 404` crashing
`/dashboard`.
A user holds an account in currency `xxx` (ISO 4217 "no/unknown
currency"). No rate file exists for it, so every candidate URL returns
404. `CurrencyConversionService::fetchRates` threw an unhandled
`RuntimeException` that bubbled past the graceful-degradation logic in
`ExchangeRateService::convert` and broke the whole dashboard render.
## Fix
Distinguish **permanent** 404s from **transient** failures:
- All sources return 404 → log a warning and return `[]`. Callers
already handle empty rates (return unconverted / zero amount).
- Timeouts / 5xx / connection errors → still throw, so real outages stay
visible.
## Tests
- New: unknown base currency with all-404 sources returns `0.0` instead
of throwing.
- Existing "throws when both primary and fallback fail" (500s) still
passes — transient errors still surface.
Fixes PHP-LARAVEL-2M.
## Summary
- **Bug fix:** Dashboard and accounts index cards displayed the
account's original currency code (e.g. `BTC`) even though balances were
already converted to the user's currency (e.g. `EUR`). Now passes
`displayCurrencyCode` to card components so the label matches the
converted amount.
- **Feature:** Added a currency toggle on the account detail chart to
switch between the account's native currency and the user's main
currency. Extends the balance evolution APIs with `display_*` fields
when conversion applies.
- **First-account restriction:** Restricts first-account creation to
primary (fiat) currencies only, ensuring the user's base currency is
always widely supported.
## Changes
### Bug fix — currency label on cards
- `AccountBalanceCard` / `AccountListCard`: Added `displayCurrencyCode`
prop; all amount renders now use it instead of `account.currency_code`
- `dashboard.tsx`: Passes `netWorthEvolution.currency_code` as
`displayCurrencyCode`
- `Accounts/Index.tsx`: Passes `auth.user.currency_code` as
`displayCurrencyCode`
### Backend — API extension
- `DashboardAnalyticsController`: Both `accountBalanceEvolution()` and
`accountDailyBalanceEvolution()` now return `display_value`,
`display_invested_amount`, `display_mortgage_balance` per data point and
a top-level `display_currency_code` when the account currency differs
from the user's
### Frontend — currency toggle
- New `ChartCurrencyToggle` component with `ToggleGroup` showing
currency code labels (e.g. `BTC` / `EUR`)
- `ChartSettingsPopover`: Extended with optional `currencyToggle` prop
for mobile
- `AccountBalanceChart`: Full integration — all amounts, trends,
tooltips, MoM chart, and equity swap to `display_*` values when toggle
is set to user currency
### First-account currency restriction
- `StoreAccountRequest`: First account limited to primary currency codes
- `AccountForm` / `CreateAccountDialog` / `StepCreateAccount`: Pass
`usePrimaryCurrenciesOnly` when applicable
### Tests
- 5 new Pest tests for `display_*` fields in balance evolution endpoints
- 3 new Vitest tests for `deriveAccountMetrics` (mixed-currency, empty
data, invested amounts)
- 1 new Pest test for first-account BTC rejection
## Summary
- Adds Binance as a third banking provider alongside EnableBanking and
Indexa Capital
- Binance appears in the institution list for **all countries**, with
the full list sorted alphabetically
- Creates a single "Crypto Portfolio" investment account with total
portfolio value converted to the user's preferred currency
- Supports direct fiat pairs (e.g. BTCEUR), USD stablecoin 1:1 mapping,
and USDT fallback conversion
## Changes
- **Migration**: adds encrypted `api_secret` column to
`banking_connections`
- **BinanceClient**: HMAC-SHA256 authenticated API client for account
data and ticker prices
- **BinanceBalanceSyncService**: converts all non-zero balances to fiat
via direct pairs or USDT fallback
- **BinanceController + ConnectBinanceRequest**: validates credentials,
creates connection and single account
- **SyncBankingConnectionJob**: new `syncBinance()` branch
- **AccountMappingController**: Binance uses Investment account type
- **Frontend**: Binance institution for all countries, API Key + Secret
form fields, alphabetically sorted list
- **Factory**: `binance()` state on `BankingConnectionFactory`
## Test plan
- [x] `BinanceControllerTest` — 6 tests (valid connection, invalid
credentials, account-mapping flag, feature flag, validation, user
currency)
- [x] `BinanceBalanceSyncTest` — 7 tests (direct EUR pair, USDT
fallback, USD stablecoins, locked balances, same-date update, empty
balances, missing external ID)
- [x] Full test suite passes (545 tests)
- [x] Manual: open connection dialog → select any country → Binance
appears alphabetically → select Binance → API Key + Secret form →
connect